Showing posts with label Linux. Show all posts
Showing posts with label Linux. Show all posts

Saturday, April 15, 2023

One-liner: Python webserver to display files

Go into linux directory that has the files you want to serve.

Start the webserver in the directory of the files you want to expose:

$ python3 -m http.server 8321


Test it from another machine by using a web browser and going to the hostname:port:

http://some-host-name.duckdns.org:8321


To persist the webserver after you log out of the shell, use nohup:

$ nohup python3 -m http.server 8321 &


Saturday, October 16, 2021

How to mine Monero on Ubuntu Linux

Please refer to the recent post about setting up a Monero pool miner on Microsoft Windows. That post provides some background information along with how to use wallet software.


Now let's focus on running a miner on Linux Ubuntu 20.04. We will use the same public key address as the previous post. We will simply change the identifier in the start file to allow both the Windows and Linux miners to be monitored on the same page at SupportXMR.com. 

Logon to the machine and determine which Ubuntu release is installed.

$ lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.3 LTS
Release:        20.04
Codename:       focal


# Create a new unix group and user.

$ sudo addgroup cryp

Adding group `cryp' (GID 1004) ...
Done.

$ grep cryp /etc/group
cryp:x:1004:

$ sudo adduser monero --ingroup cryp
Adding user `monero' ...
Adding new user `monero' (1005) with group `cryp' ...
Creating home directory `/home/monero' ...
Copying files from `/etc/skel' ...
New password:
Retype new password:
passwd: password updated successfully
Changing the user information for monero
Enter the new value, or press ENTER for the default
        Full Name []:
        Room Number []:
        Work Phone []:
        Home Phone []:
        Other []:
Is the information correct? [Y/n] y

# If you want the new monero Linux user to be able to log on to the machine remotely, add user monero to the "AllowUsers" line in /etc/ssh/sshd_config.
$ sudo vi /etc/ssh/sshd_config

# Now edit the config file and add the monero username.
$ grep monero /etc/ssh/sshd_config
AllowUsers install1 minec monero

# Restart ssh to apply the new configuration.
$ sudo systemctl restart ssh

# ssh into the machine as the monero user.
$ whoami
monero

$ groups
cryp

$ id
uid=1005(monero) gid=1004(cryp) groups=1004(cryp)


# Earlier we ran "lsb_release -a" it showed the name "focal" for the Ubuntu release. Get the monero software, with the matching Ubuntu release name, from https://github.com/xmrig/xmrig/releases.

$ wget https://github.com/xmrig/xmrig/releases/download/v6.15.2/xmrig-6.15.2-focal-x64.tar.gz 

$ gzip -d xmrig-6.15.2-focal-x64.tar.gz

$ tar -xvf xmrig-6.15.2-focal-x64.tar
xmrig-6.15.2/
xmrig-6.15.2/config.json
xmrig-6.15.2/SHA256SUMS
xmrig-6.15.2/xmrig

$ ls -l
total 8256
drwxr-x--- 2 monero cryp    4096 Oct  5 10:38 xmrig-6.15.2
-rw-r----- 1 monero cryp 8448000 Oct  5 11:30 xmrig-6.15.2-focal-x64.tar


# Go into the software directory and create a new (or replace the example) config.json.
$ cd xmrig-6.15.2
$ ls -l
total 8256
-rw-r----- 1 monero cryp    2351 Oct  5 10:38 config.json
-rw-r----- 1 monero cryp     150 Oct  5 10:38 SHA256SUMS
-rwxr-x--- 1 monero cryp 8441704 Oct  5 10:38 xmrig

# Put the following into file config.json. Note the "user" public key is on one line.
$ cat config.json
{
"autosave": true,
"cpu": true,
"opencl": false,
"cuda": false,
"pools": [
        {
                "url": "pool.supportxmr.com:443",
                "user": "44YkNzrdJnmAqwoTRMPV2e4fihv3AfZ5vMmrtaWCGQaxKuXp5eiZeRREzhPi9tVqGuA3VBRriNwKa2QxmZmRGmHVTkUSTMc",
                "pass": "runDemoB",
                "keepalive": true,
                "tls": true
        }
        ]
}


# Test it from the command line. Stop the program with ctrl-c after you verify it is working.
$ ./xmrig -c ./config.json




# Create and test a command file which will be used by the Linux process monitor so the miner will be started upon machine reboot.
$ cd ~
$ pwd
/home/monero

# Put these three lines into the command file named startminer.sh. Note the last command is all one line.
$ vi startminer.sh
#!/bin/sh
umask 026
/usr/bin/nice -n 15 /home/monero/xmrig-6.15.2/xmrig -c /home/monero/xmrig-6.15.2/config.json

# Make the file executable.
$ chmod +x startminer.sh

# Test the command file from the command line.
$ ./startminer.sh

# In another terminal window, run "top" and look at the "NI" column. It should be the "nice" value in the command file. This sets the process priority lower, so the machine can more easily prioritize other work (if there is other work).


# Configure the system services so the mining process will automatically start with the machine.
# For the following commands with sudo, log in with a unix account which is in the sudoers file.
$ cd /etc/systemd/system
$ sudo vi monero.service
[Unit]
Description=monero miner
After=network.target
[Service]
Type=simple
User=monero
Group=cryp
ExecStart=/home/monero/startminer.sh
KillMode=mixed
Restart=on-failure
Type=forking
TimeoutStartSec=120
TimeoutStopSec=30
RuntimeMaxSec=infinity
[Install]
WantedBy=multi-user.target

# Enable the service.
$ sudo systemctl enable monero.service
Created symlink /etc/systemd/system/multi-user.target.wants/monero.service → /etc/systemd/system/monero.service.

$ sudo systemctl start monero.service
$ sudo systemctl status monero.service

# Run top or htop to confirm the miner is running with the specified "nice" level.
# Reboot the machine to test the miner will restart automatically.
$ sudo shutdown -r

# After machine restarts, login and run the following to verify the service is running and that it is only running one.
$ top
$ htop
$ ps -fu monero

Let's look into the mining process a little closer, and focus on the number of tasks or processes that are run. From a defensive system administration standpoint, we may want to configure the service so it can not errantly consume thousands of processes.

With the miner running as a service, it is currently using just a handful of processes. This seems to be correct, as one process per CPU core (in this case 4 cores) is reasonable.

$ ps -fu monero
UID          PID    PPID  C STIME TTY          TIME CMD
monero      1046       1  0 15:02 ?        00:00:00 /lib/systemd/systemd --user
monero      1047    1046  0 15:02 ?        00:00:00 (sd-pam)
monero      1145    1043  0 15:02 ?        00:00:00 sshd: monero@pts/0
monero      1146    1145  0 15:02 pts/0    00:00:00 -bash
monero      1471       1  0 15:10 ?        00:00:00 /bin/sh /home/monero/startminer.sh
monero      1472    1471 99 15:10 ?        00:05:38 /home/monero/xmrig-6.15.2/xmrig -c /home/monero/xmrig-6.15.2/c
monero      1517    1146  0 15:12 pts/0    00:00:00 ps -fu monero

$ ps -fu monero | wc -l
9


# In another terminal window with a Linux user which has access to sudo.
$ sudo systemctl status monero.service
● monero.service - monero miner
     Loaded: loaded (/etc/systemd/system/monero.service; enabled; vendor preset: enabled)
     Active: activating (start) since Sun 2021-10-10 15:12:24 MDT; 1min 57s ago
Cntrl PID: 1531 (startminer.sh)
      Tasks: 10 (limit: 18964)
     Memory: 2.2G
     CGroup: /system.slice/monero.service
             ├─1531 /bin/sh /home/monero/startminer.sh
             └─1532 /home/monero/xmrig-6.15.2/xmrig -c /home/monero/xmrig-6.15.2/config.json
Oct 10 15:12:38 d990 startminer.sh[1532]: [2021-10-10 15:12:38.338]  net      new job from pool.>
Oct 10 15:12:38 d990 startminer.sh[1532]: [2021-10-10 15:12:38.338]  cpu      use argon2 impleme>
Oct 10 15:12:38 d990 startminer.sh[1532]: [2021-10-10 15:12:38.341]  msr      msr kernel module >
Oct 10 15:12:38 d990 startminer.sh[1532]: [2021-10-10 15:12:38.341]  msr      FAILED TO APPLY MS>
Oct 10 15:12:38 d990 startminer.sh[1532]: [2021-10-10 15:12:38.342]  randomx  init dataset algo >
Oct 10 15:12:38 d990 startminer.sh[1532]: [2021-10-10 15:12:38.342]  randomx  allocated 2336 MB >
Oct 10 15:12:45 d990 startminer.sh[1532]: [2021-10-10 15:12:45.958]  randomx  dataset ready (761>
Oct 10 15:12:45 d990 startminer.sh[1532]: [2021-10-10 15:12:45.958]  cpu      use profile  rx  (>
Oct 10 15:12:45 d990 startminer.sh[1532]: [2021-10-10 15:12:45.960]  cpu      READY threads 3/3 >
Oct 10 15:13:46 d990 startminer.sh[1532]: [2021-10-10 15:13:46.126]  miner    speed 10s/60s/15m >

$ systemctl show --property DefaultTasksMax
DefaultTasksMax=18964

# Note the service is using 10 tasks of the 18964 limit. It appears it uses the default maximum setting.
# Note the service is using 2.2 GB of memory.
# Since the service is running correctly and the machine has four CPU cores, let's ensure the service does not run away. Limit it to no more than 999 processes.

# Add two lines to the end of /etc/systemd/system/monero.service.
[Service]
TasksMax=999

# Reload the systemd configuration.
$ sudo systemctl daemon-reload

# Restart the mining process.
$ sudo systemctl restart monero.service

# Look at the Tasks limit for this mining process. It should use 999 from the monero.service file.
$ systemctl status monero.service | grep Tasks
      Tasks: 10 (limit: 999)

# Restart the machine to test the configuration.
$ sudo shutdown -r


Go to the SupportXMR.com website to monitor the mining activity. Enter the address from the config file at this website to see your miner activity.

Using top and htop, you may notice with four CPU cores that it seems only three are being used. The load average will be in the 3s rather than 4 (the number of cores). For this example on this four-core CPU, you may edit config.json and add the fourth core to the "rx" line, like this: "rx": [0, 1, 2, 3],

# Then restart the service.
$ sudo systemctl restart monero.service

# If you make this change to use more CPU, closely monitor if more hashes are being calculated. You may find that while more CPU is used, less hashes are performed due to CPU cache issues. Please read this tuning document and consider de-tuning to the prior setup. In short, hyper-threading (more logical processors than cores) usually does not scale CPU-bound processes.



To tune the OS settings, look into huge pages. First, get the current settings and monitor the current miner hash rate so you know the baseline before making tuning changes.

Without tuning, the OS may be configured like this:

$ grep -i huge /proc/meminfo
AnonHugePages:         0 kB
ShmemHugePages:        0 kB
FileHugePages:         0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
Hugetlb:               0 kB

Stop the miner process, make temporary changes to OS kernel settings, and restart the miner to determine if the hash rate changes.

$ sudo sysctl -w vm.nr_hugepages=1280
$ grep -i huge /proc/meminfo
AnonHugePages:         0 kB
ShmemHugePages:        0 kB
FileHugePages:         0 kB
HugePages_Total:    1280
HugePages_Free:     1280
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
Hugetlb:         2621440 kB

If the restarted miner process shows an increase in hashing, then make the kernel OS settings permanent.

$ sudo bash -c "echo vm.nr_hugepages=1280 >> /etc/sysctl.conf"

Reboot the machine and check the huge pages setting and the miner hash rate. For this example, the per second hash rate went from 965 to 1381 just by tuning huge pages.

Monday, July 19, 2021

Ubuntu logon info and message of the day (motd)

This post will show you how to determine your public-facing IP address from the command line.


Upon an interactive logon, Ubuntu prints some brief machine information. This includes a header, sysinfo from /usr/bin/landscape-sysinfo and a summary of available patches.

You may add your own scripts by creating a bash script in /etc/update-motd.d and set the execute permission on the file. The files in the directory have a particular naming convention, and are run in alphabetical (numeric) order.

On external facing machines, I often create a script which will print the external IP address following the networking info of the landscape-sysinfo script.

Create file /etc/update-motd.d/61-external-ip owned by root
and give it execute permission:
sudo chmod 755 /etc/update-motd.d/61-external-ip

 

Place the following in this new file:
#!/bin/sh

ONE=$(/usr/bin/curl -s checkip.amazonaws.com)
TWO=$(/usr/bin/curl -s ifconfig.me)

if [ $ONE = $TWO ]
  then
    printf "  External IPv4: "
    printf $ONE
  else
    printf "  External IPv4 may be: "
    printf $ONE
    printf " or"
    printf $TWO
fi
printf "\n"


Save the file, then logon to the machine and look at the interactive logon messages. Some of the output will look like:

Welcome to Ubuntu 20.04.2 LTS (GNU/Linux 5.4.0-77-generic x86_64)

  System information as of Mon 19 Jul 2021 01:30:42 PM MDT

  System load:              0.58
  Usage of /:               5.4% of 1.79TB
  Memory usage:             15%
  Swap usage:               0%
  Temperature:              44.0 C
  Processes:                173
  Users logged in:          1
  IPv4 address for enp0s25: 192.168.0.9
  External IPv4: 123.456.7.89

Saturday, June 13, 2020

Install PostgreSQL on Ubuntu 20.04

Let's install a recent version of Postgresql on Ubuntu 20.04. You will need a unix account with sudo privilege. At the end of this post we will do some introductory database commands.

Get familiar with the Linux install:
$ uname -a
Linux d990 5.4.0-37-generic #41-Ubuntu SMP Wed Jun 3 18:57:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
 

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04 LTS
Release:        20.04
Codename:       focal
 

$ df -k
Filesystem      1K-blocks     Used  Available Use% Mounted on
udev              8093132        0    8093132   0% /dev
tmpfs             1627360     1260    1626100   1% /run
/dev/sda2      1921800384 30477352 1793631080   2% /
tmpfs             8136796        0    8136796   0% /dev/shm
tmpfs                5120        0       5120   0% /run/lock
tmpfs             8136796        0    8136796   0% /sys/fs/cgroup
/dev/loop0         160000   160000          0 100% /snap/chromium/1165
/dev/loop2          56320    56320          0 100% /snap/core18/1754
/dev/loop3          63616    63616          0 100% /snap/gtk-common-themes/1506
/dev/loop1          56320    56320          0 100% /snap/core18/1705
/dev/loop7          27776    27776          0 100% /snap/snapd/7264
/dev/loop6          71040    71040          0 100% /snap/lxd/15457
/dev/loop4         160000   160000          0 100% /snap/chromium/1182
/dev/loop5          31104    31104          0 100% /snap/snapd/7777
/dev/loop8          71040    71040          0 100% /snap/lxd/15359
tmpfs             1627356        8    1627348   1% /run/user/1004



Update Ubuntu Linux:
$ sudo apt-get update
$ sudo apt-get upgrade



Read these instructions to set up apt to get the recent Postgresql release. Simply follow-along with the instructions from the link.
# Create the file repository configuration:
sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list'

# Import the repository signing key:
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -

# Update the package lists:
sudo apt-get update

# Install the latest version of PostgreSQL.
# If you want a specific version, use 'postgresql-12' or similar instead of 'postgresql':
sudo apt-get install postgresql


The command "install postgresql" will run for a minute or two. It should end with:
Success. You can now start the database server using:
    pg_ctlcluster 12 main start

Look at the new unix account "postgres". Note it does have a password to log in to unix:
$ cat /etc/group|tail -1
postgres:x:118:
$ cat /etc/passwd|tail -1
postgres:x:112:118:PostgreSQL administrator,,,:/var/lib/postgresql:/bin/bash


$ sudo grep postgres /etc/shadow
postgres:*:18427:0:99999:7:::


Look at what is running:
$ ps -fu postgres
UID          PID    PPID  C STIME TTY          TIME CMD
postgres  148055       1  0 21:06 ?        00:00:00 /usr/lib/postgresql/12/bin/postgres -D /var/lib/po
postgres  148060  148055  0 21:06 ?        00:00:00 postgres: 12/main: checkpointer
postgres  148061  148055  0 21:06 ?        00:00:00 postgres: 12/main: background writer
postgres  148062  148055  0 21:06 ?        00:00:00 postgres: 12/main: walwriter
postgres  148063  148055  0 21:06 ?        00:00:00 postgres: 12/main: autovacuum launcher
postgres  148064  148055  0 21:06 ?        00:00:00 postgres: 12/main: stats collector
postgres  148065  148055  0 21:06 ?        00:00:00 postgres: 12/main: logical replication launcher
postgres  149432  149431  0 21:16 pts/1    00:00:00 -bash



Check the service manager to see if the database startup is automated:
$ systemctl status postgresql
● postgresql.service - PostgreSQL RDBMS
     Loaded: loaded (/lib/systemd/system/postgresql.service; enabled; vendor preset: enabled)
     Active: active (exited) since Sat 2020-06-13 21:06:29 MDT; 14h ago
   Main PID: 147715 (code=exited, status=0/SUCCESS)
      Tasks: 0 (limit: 18968)
     Memory: 0B
     CGroup: /system.slice/postgresql.service




To allow connections from outside the machine, edit the postgresql.conf file and add a line for listen_addresses. Then restart postgresql.
$ grep listen /etc/postgresql/12/main/postgresql.conf
listen_addresses = '*'

You may also need to edit pg_hba.conf, to allow connections from outside the machine.


Software versions:
$ psql -V
psql (PostgreSQL) 12.3 (Ubuntu 12.3-1.pgdg20.04+1)


Let's create a database, list the databases, create a table with a couple rows, and select from the table. From unix command-line, connect via psql:
$ psql
psql (12.3 (Ubuntu 12.3-1.pgdg20.04+1))
Type "help" for help.



postgres=# create database datadb;
CREATE DATABASE

postgres=# \l
                                  List of databases
   Name    |  Owner   | Encoding |   Collate   |    Ctype    |   Access privileges
-----------+----------+----------+-------------+-------------+-----------------------
 datadb    | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
 postgres  | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
 template0 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
           |          |          |             |             | postgres=CTc/postgres
 template1 | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
           |          |          |             |             | postgres=CTc/postgres
(4 rows)

postgres=# \c datadb
You are now connected to database "datadb" as user "postgres".

datadb=# create table testtable (columna text not null, columnb int not null);
CREATE TABLE

datadb=# insert into testtable values ('insertrowone', 1);
INSERT 0 1

datadb=# insert into testtable values ('insertrowtwo', 2);
INSERT 0 1

datadb=# select * from testtable;
   columna    | columnb
--------------+---------
 insertrowone |       1
 insertrowtwo |       2
(2 rows)

datadb=# \q

Sunday, May 10, 2020

Ubuntu Linux High CPU For Swap Process

What do you do if you just installed a fresh Ubuntu 20.04 server, and after installing some packages with "apt" you notice high CPU usage from the swap process?

If "top" shows kswapd0 persistently using high CPU, and "freemem -d" and swap are ok, you can try to adjust the swappiness in file sysctl.conf and reboot.
$ cat /proc/sys/vm/swappiness
60
$ sudo vi /etc/sysctl.conf
$ cat /etc/sysctl.conf | grep vm
vm.swappiness=10


Changing swappiness didn't fix this problem of high CPU usage. Let's dig deep.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04 LTS
Release:        20.04
Codename:       focal
install@d990 ~ $ uname -a
Linux d990 5.4.0-29-generic #33-Ubuntu SMP Wed Apr 29 14:32:27 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux


Look closely at "top" output.
$ top
top - 19:03:26 up 7 min,  3 users,  load average: 3.09, 2.72, 1.44
Tasks: 132 total,   1 running, 131 sleeping,   0 stopped,   0 zombie
%Cpu(s): 76.3 us,  0.4 sy,  0.0 ni, 23.2 id,  0.1 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :  15892.2 total,  10206.3 free,   4412.8 used,   1273.1 buff/cache
MiB Swap:   4096.0 total,   4096.0 free,      0.0 used.  11199.7 avail Mem

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
   1071 kevin     20   0 2435108   2.3g   1480 S 300.0  14.7  20:50.80 kswapd0   1147 minec     20   0 7861400   1.9g  28544 S   6.6  11.9   1:54.40 java
      1 root      20   0  167604  11524   8368 S   0.0   0.1   0:00.98 systemd
      2 root      20   0       0      0      0 S   0.0   0.0   0:00.00 kthreadd
      3 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_gp
      4 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_par+
      6 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 kworker+
      8 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 mm_perc+
      9 root      20   0       0      0      0 S   0.0   0.0   0:00.01 ksoftir+
     10 root      20   0       0      0      0 I   0.0   0.0   0:00.13 rcu_sch+
     11 root      rt   0       0      0      0 S   0.0   0.0   0:00.00 migrati+
     12 root     -51   0       0      0      0 S   0.0   0.0   0:00.00 idle_in+
     13 root      20   0       0      0      0 I   0.0   0.0   0:00.01 kworker+
     14 root      20   0       0      0      0 S   0.0   0.0   0:00.00 cpuhp/0
     15 root      20   0       0      0      0 S   0.0   0.0   0:00.00 cpuhp/1
     16 root     -51   0       0      0      0 S   0.0   0.0   0:00.00 idle_in+
     17 root      rt   0       0      0      0 S   0.0   0.0   0:00.14 migrati+


$ top -u kevin
top - 19:03:59 up 8 min,  3 users,  load average: 3.05, 2.75, 1.49
Tasks: 132 total,   1 running, 131 sleeping,   0 stopped,   0 zombie
%Cpu(s): 76.3 us,  0.3 sy,  0.0 ni, 23.1 id,  0.3 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :  15892.2 total,  10205.5 free,   4413.5 used,   1273.2 buff/cache
MiB Swap:   4096.0 total,   4096.0 free,      0.0 used.  11199.0 avail Mem

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
   1071 kevin     20   0 2435108   2.3g   1480 S 300.3  14.7  22:28.66 kswapd0
   1015 kevin     20   0   14368   6760   2800 S   0.0   0.0   0:00.00 rsync



Why is kevin in charge of swap? Kevin has yet to log in to the system.
$ last kevin

wtmp begins Sat May  9 18:16:21 2020
 

$ groups kevin
kevin : kevin
 

$ sudo grep kevin /etc/sudoers
 

$ ps -fu kevin
UID          PID    PPID  C STIME TTY          TIME CMD
kevin       1015       1  0 18:56 ?        00:00:00 rsync
kevin       1071       1 99 18:56 ?        00:11:53 ./kswapd0



We know kevin has not logged in, is only in his own group, and does not have sudo. This was the most recent account we created on the machine.
$ tail -1 /etc/passwd
kevin:x:1005:1004:,,,,novice tech learner:/home/kevin:/bin/bash



Comment out the entry in the passwd file.
$ tail -1 /etc/passwd
kevin:x:1005:1004:,,,,novice tech learner:/home/kevin:/bin/bash
 

$ sudo vi /etc/passwd
 

$ tail -1 /etc/passwd
#kevin:x:1005:1004:,,,,novice tech learner:/home/kevin:/bin/bash


Run top, and it won't know the "kevin" username for uid 1005. It is still consuming CPU.
$ top
top - 19:08:43 up 13 min,  3 users,  load average: 3.13, 2.96, 1.92
Tasks: 130 total,   1 running, 129 sleeping,   0 stopped,   0 zombie
%Cpu(s): 76.2 us,  0.6 sy,  0.0 ni, 23.0 id,  0.3 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :  15892.2 total,  10198.5 free,   4413.8 used,   1279.9 buff/cache
MiB Swap:   4096.0 total,   4096.0 free,      0.0 used.  11198.6 avail Mem

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
   1071 1005      20   0 2435108   2.3g   1480 S 300.7  14.7  36:40.32 kswapd0
   1147 minec     20   0 7861400   1.9g  28544 S   6.7  11.9   2:14.81 java
    375 root      20   0       0      0      0 S   0.3   0.0   0:00.01 jbd2/sd+
      1 root      20   0  167604  11524   8368 S   0.0   0.1   0:01.00 systemd
      2 root      20   0       0      0      0 S   0.0   0.0   0:00.00 kthreadd
      3 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_gp
      4 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_par+
      6 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 kworker+
      8 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 mm_perc+
 


With the passwd entry for kevin commented out, let's reboot and observe what happens.
$ sudo systemctl reboot

$ top
top - 19:14:04 up 1 min,  1 user,  load average: 1.35, 0.61, 0.23
Tasks: 138 total,   1 running, 137 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.3 us,  0.4 sy,  0.0 ni, 99.3 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :  15892.2 total,  12795.1 free,   1850.3 used,   1246.8 buff/cache
MiB Swap:   4096.0 total,   4096.0 free,      0.0 used.  13763.3 avail Mem

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
    898 minec     20   0 7861400   1.7g  28288 S   6.3  10.7   1:20.07 java
    156 root      20   0       0      0      0 I   0.3   0.0   0:00.16 kworker+
    443 root      19  -1  133560  61216  60108 S   0.3   0.4   0:00.61 systemd+
   1206 root      20   0   13416   8268   7096 S   0.3   0.1   0:00.01 sshd
   1207 sshd      20   0   12160   4616   3708 S   0.3   0.0   0:00.01 sshd
      1 root      20   0  167744  11508   8440 S   0.0   0.1   0:03.25 systemd
      2 root      20   0       0      0      0 S   0.0   0.0   0:00.00 kthreadd
      3 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_gp
      4 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_par+


Let's remove the kevin account properly. Uncomment the line in /etc/passwd and delete the account.
$ sudo vi /etc/passwd
 

$ sudo userdel -r kevin
$ grep kevin /etc/passwd

$ uptime
 19:15:53 up 3 min,  1 user,  load average: 0.21, 0.42, 0.20


Reboot and look for normal functioning.
$ sudo systemctl reboot



Install Ubuntu 20.04 Server

The server version of Ubuntu had previously been tuned for server-oriented workloads. This is reportedly no longer the case, so a primary difference between Ubuntu 20 server and desktop is that server lacks a graphical user interface.

Download an image from the Ubuntu releases page. Most everything is 64 bit. Note that "AMD" means it works on the AMD and Intel instruction sets. You can use the AMD64 image on a modern Intel CPU.

Burn the image to a DVD or other mountable storage. Boot the machine from the storage. This install will use hard-wired Ethernet and a static IP address. If you have a real (typically non-consumer internet service) domain name, use that as the "search domain".







































This is a server install, so maybe you do not want "games" in your search path. Backup the "environment" file then remove the games directory from the search path.
$ sudo mv /etc/environment /etc/environment.orig
$ sudo vi /etc/environment
$ cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"


Modify the shell login files in your home directory.
$ cd ~
$ cp -p .bashrc .bashrc.orig
$ mv .profile .profile.orig
$ mv .bashrc .bash_profile

Remove colorization by setting TERM environment variable in .bash_profile.
$ echo $TERM
xterm-256color
$ export TERM=xterm-mono

Edit .bash_profile and put in a bit of color to the command prompt variable PS1.
$ grep 033 ~/.bash_profile
PS1='\[\033[01;32m\]\u@\h\[\033[00m\] \w \$ '


Put the present working directory at the end of the PATH variable. Add this to file .bash_profile.

export PATH=$PATH:.
Remove shell's suggestions for a mis-typed command. Add this to file .bash_profile.
unset command_not_found_handle

Then "source" the login files or simply log out and log in again.
$ ./.bash_profile


Get familiar with the install and the machine.
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04 LTS
Release:        20.04
Codename:       focal
 


$ uname -a
Linux d990 5.4
.0-26-generic #30-Ubuntu SMP Mon Apr 20 16:58:30 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
 

$ lspci
00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
00:16.3 Serial controller: Intel Corporation 6 Series/C200 Series Chipset Family KT Controller (rev 04)
00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (Lewisville) (rev 04)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b4)
00:1c.2 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 3 (rev b4)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev a4)
00:1f.0 ISA bridge: Intel Corporation Q67 Express Chipset LPC Controller (rev 04)
00:1f.2 RAID bus controller: Intel Corporation SATA Controller [RAID mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 04)
 

$ df -k
Filesystem      1K-blocks    Used  Available Use% Mounted on
udev              8093172       0    8093172   0% /dev
tmpfs             1627360    1204    1626156   1% /run
/dev/sda2      1921800384 9591096 1814517336   1% /
tmpfs             8136796       0    8136796   0% /dev/shm
tmpfs                5120       0       5120   0% /run/lock
tmpfs             8136796       0    8136796   0% /sys/fs/cgroup
/dev/loop0          27776   27776          0 100% /snap/snapd/7264
/dev/loop1          56320   56320          0 100% /snap/core18/1705
/dev/loop2          70656   70656          0 100% /snap/lxd/14804
tmpfs             1627356       0    1627356   0% /run/user/1000


Familiarize yourself with the network configuration.
$ ls -l /etc/netplan
total 4
-rw-r--r-- 1 root root 280 May 10 00:03 00-installer-config.yaml

$ cat /etc/netplan/00-installer-config.yaml
# This is the network config written by 'subiquity'
network:
  ethernets:
    enp0s25:
      addresses:
      - 192.168.0.9/24
      gateway4: 192.168.0.1
      nameservers:
        addresses:
        - 1.1.1.1
        - 8.8.8.8
        search:
        - duckdns.org
  version: 2



Look at the syslog.
$ sudo tail /var/log/syslog

Look at the running processes, then look at running services.
$ ps -ef | more
$ systemctl list-units --all --type=service --no-pager

Let's remove a service we don't want automatically started, and one we don't need.
$ sudo systemctl stop rsync
$ sudo systemctl disable rsync

$ systemctl status vgauth
● vgauth.service - Authentication service for virtual machines hosted on VMware
     Loaded: loaded (/lib/systemd/system/vgauth.service; enabled; vendor preset: enabled)
     Active: inactive (dead)
  Condition: start condition failed at Sun 2020-05-10 00:16:27 UTC; 2h 30min ago
       Docs: http://github.com/vmware/open-vm-tools

May 10 00:16:27 d990 systemd[1]: Condition check resulted in Authentication service for virtual machines hosted on VMware being skipped.


$ sudo systemctl stop vgauth
$ sudo systemctl disable vgauth

$ systemctl status open-vm-tools
● open-vm-tools.service - Service for virtual machines hosted on VMware
     Loaded: loaded (/lib/systemd/system/open-vm-tools.service; enabled; vendor preset: enabled)
     Active: inactive (dead)
  Condition: start condition failed at Sun 2020-05-10 02:56:23 UTC; 3min 54s ago
       Docs: http://open-vm-tools.sourceforge.net/about.php

May 10 02:56:23 d990 systemd[1]: Condition check resulted in Service for virtual machines hosted on VMware being skipped.
 

$ sudo systemctl stop open-vm-tools
[sudo] password for install:
 

$ sudo systemctl disable open-vm-tools
Synchronizing state of open-vm-tools.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install disable open-vm-tools
Removed /etc/systemd/system/multi-user.target.wants/open-vm-tools.service.
 

$ systemctl status open-vm-tools
● open-vm-tools.service - Service for virtual machines hosted on VMware
     Loaded: loaded (/lib/systemd/system/open-vm-tools.service; indirect; vendor preset: enabled)
     Active: inactive (dead)
       Docs: http://open-vm-tools.sourceforge.net/about.php

May 10 02:56:23 d990 systemd[1]: Condition check resulted in Service for virtual machines hosted on VMware being skipped.


This is a server machine, so we don't need this process attaching to a sound card.
$ apt list pulseaudio
Listing... Done
pulseaudio/focal-updates 1:13.99.1-1ubuntu3.5 amd64 [upgradable from: 1:13.99.1-1ubuntu3.3]
N: There are 3 additional versions. Please use the '-a' switch to see them.
$ sudo apt remove pulseaudio

 
Since this is a server install, the majority of the time it will be accessed remotely. A person using an X display may want to work with images, so install an image viewer such as eog.
$ sudo apt install eog


Disable printing of Ubuntu newswire during shell logon.
$ sudo chmod -x /etc/update-motd.d/50-motd-news

Note the firewall is not active.
$ sudo ufw status
Status: inactive


Install software updates. You may need to reboot the machine to apply all software updates.
$ sudo apt update
$ sudo apt upgrade
$ sudo systemctl reboot

Familiarize yourself with users and groups.
$ cat /etc/passwd
$ cat /etc/group

Put in users and groups.
$ sudo addgroup minecrft
Adding group `minecrft' (GID 1001) ...
Done.
$ sudo adduser minec --ingroup minecrft
Adding user `minec' ...
Adding new user `minec' (1001) with group `minecrft' ...


On a consumer-type internet connection, you may want to configure a dynamic DNS service such as DuckDNS. Create the user, get your information from duckdns.org, then configure software.
$ sudo addgroup duckdns
$ sudo adduser duckdns --ingroup duckdns
Read this to configure the software and crontab entry for duckdns.


Let's change the time zone to Amsterdam.
$ cat /etc/timezone
Etc/UTC
$ timedatectl
               Local time: Sun 2020-05-10 19:12:56 UTC
           Universal time: Sun 2020-05-10 19:12:56 UTC
                 RTC time: Sun 2020-05-10 19:12:56
                Time zone: Etc/UTC (UTC, +0000)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

$ timedatectl list-timezones | grep -i ams
Europe/Amsterdam
 

$ sudo timedatectl set-timezone Europe/Amsterdam
 

$ cat /etc/timezone
Europe/Amsterdam

$ timedatectl
               Local time: Sun 2020-05-10 21:14:02 CEST
           Universal time: Sun 2020-05-10 19:14:02 UTC
                 RTC time: Sun 2020-05-10 19:14:02
                Time zone: Europe/Amsterdam (CEST, +0200)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no


 

While we could try to disable the cloud initialization with
$ touch /etc/cloud/cloud-init-disabled
Let's remove it.
$ sudo apt remove cloud-init


Optionally, install X server.
$ sudo apt install tightvncserver
$ sudo apt install xterm
Then configure your .Xresources file.


Optionally, install javascript runtime via apt.
$ sudo apt install nodejs
$  which node
/usr/bin/nodejs
$ nodejs --version
v10.19.0

$ sudo apt install chromium-browser
$ which chromium-browser
/usr/bin/chromium-browser

Optionally, upgrade the node software.
$ curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -
$ sudo apt install nodejs
$ which node
/usr/bin/node
$ node -v
v12.16.3
$ npm -v
6.14.4



Anyone editing files with vim (vi is typically vim) may want to learn the basics of the .vimrc startup file.
$ cat ~/.vimrc
syntax off
set showmatch
set hlsearch
set matchpairs+=<:>,(:),{:},[:]

:nmap <F1> <nop>


For a graphical editor, install nedit.
$ sudo apt install nedit


Familiarize yourself with memory and disk space, network interfaces and networking, and how the machine is running.  Review the output from the following commands.
Since ifconfig is deprecated, use the ip command. Instead of traceroute, use the mtr command.
$ free -m
$ df -k
$ sudo lshw


$ landscape-sysinfo
$ top
$ htop


$ ip a
$ mtr wunderground.com 

__________________________________________________________

Update of this blog post with more readable explanation of network settings to be used during install from the console. These examples use IP address 192.168.0.6.
















$ ls -l /etc/netplan
total 4
-rw-r--r-- 1 root root 260 Oct 16 21:13 00-installer-config.yaml

$ cat /etc/netplan/*
# This is the network config written by 'subiquity'
network:
  ethernets:
    enp5s0:
      addresses:
      - 192.168.0.6/24
      gateway4: 192.168.0.1
      nameservers:
        addresses:
        - 1.1.1.1
        - 8.8.8.8
        search: []
  version: 2

$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether bc:30:5b:e7:a4:f9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.6/24 brd 192.168.0.255 scope global enp5s0
       valid_lft forever preferred_lft forever
    inet6 fe80::be30:5bff:fee7:a4f9/64 scope link
       valid_lft forever preferred_lft forever

Sunday, April 26, 2020

Install Apache On Ubuntu Linux

Install the Apache web server on Ubuntu Linux. You will need to be able to install software and start services, so this example uses a Linux account with full sudo. In this example the Linux user name is "testuser".

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.4 LTS
Release:        18.04
Codename:       bionic


$ hostname -I
192.168.0.9


$ sudo ufw status
Status: inactive


# Update package list and install Apache.

$ sudo apt update
...
Fetched 2,854 kB in 2s (1,395 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
All packages are up to date.

$ sudo apt install apache2
...
Created symlink /etc/systemd/system/multi-user.target.wants/apache2.service → /lib/systemd/system/apache2.service.
Created symlink /etc/systemd/system/multi-user.target.wants/apache-htcacheclean.service → /lib/systemd/system/apache-htcacheclean.service.
...

# Note the screen output shows symlinks in the configuration directories for the system services.
 

# Let's see what was is running.
$ systemctl status apache2.service
● apache2.service - The Apache HTTP Server
   Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
  Drop-In: /lib/systemd/system/apache2.service.d
           └─apache2-systemd.conf
   Active: active (running) since Sun 2020-04-26 12:08:28 MDT; 2min 6s ago
 Main PID: 29916 (apache2)
    Tasks: 55 (limit: 4915)
   CGroup: /system.slice/apache2.service
           ├─29916 /usr/sbin/apache2 -k start
           ├─29918 /usr/sbin/apache2 -k start
           └─29919 /usr/sbin/apache2 -k start



# Use a web browser to go to the machine name or IP address.
# Earlier you found the IP address by typing "hostname -I".



# It is kind of the developers and package maintainers to put instructions on the home page! 

# Let's look at the index.html file.
$ cd /var/www/html
$ ls -l
total 12
-rw-r--r-- 1 root root 10918 Apr 26 12:08 index.html

# Being owned by root, we can guess an "apache" unix logon was not created.
$ grep apa /etc/passwd
# Nothing found. Also look at last line of /etc/passwd for a new entry.
$ tail -1 /etc/passwd

# Since software often has errors, bugs, and security holes, an attacker may exploit those
# holes and possibly gain access as the user which is running the software.
# The apache software is being run as root. It had better be perfect software!
# Let's look further.

$ ps -ef | grep apache
root     29916     1  0 12:08 ?        00:00:00 /usr/sbin/apache2 -k start
www-data 29918 29916  0 12:08 ?        00:00:00 /usr/sbin/apache2 -k start
www-data 29919 29916  0 12:08 ?        00:00:00 /usr/sbin/apache2


# Processes are running both as root and as the pre-existing unix logon www-data.

# Let's see if www-data is a less-privileged account than root
$ groups www-data
www-data : www-data
$ sudo grep www /etc/sudoers

# No output from grep, so it looks like www-data doesn't have sudo. This is good.
# To open a listening connection on a "low numbered port", you typically need to be root.
# Maybe that is why part of the web server is started as root. This is something to further explore.

# For now, let's change the static web page served from the file index.html.
$ cd /var/www/html
$ ls -l
total 12
-rw-r--r-- 1 root root 10918 Apr 26 12:08 index.html
$ sudo cp index.html index.html.orig
$ ls -l
total 24
-rw-r--r-- 1 root root 10918 Apr 26 12:08 index.html
-rw-r--r-- 1 root root 10918 Apr 26 12:29 index.html.orig


# Edit the file and add some text.  When editing the file, search for "welcome" and change the text.
$ sudo vi index.html
# In the "content_section_text", you may want to add a new paragraph tags and a couple lines such as:
<p>
“I'm a great believer in luck, and I find the harder I work the more I have of it.”
<a href="https://plato.stanford.edu/entries/jefferson">Thomas Jefferson</a>
</p>

# Reload your web browser to see your changes.



# Verify that systemctl is set up properly to start and stop the web server.
$ sudo systemctl stop apache2.service
$ ps -ef|grep apac
testuser       32236 28823  0 14:58 pts/0    00:00:00 grep apac


$ sudo systemctl start apache2.service
$ ps -ef | grep apac
root     32262     1  0 14:58 ?        00:00:00 /usr/sbin/apache2 -k start
www-data 32264 32262  0 14:58 ?        00:00:00 /usr/sbin/apache2 -k start
www-data 32265 32262  0 14:58 ?        00:00:00 /usr/sbin/apache2 -k start
testuser       32327 28823  0 14:58 pts/0    00:00:00 grep apac

$ systemctl status apache2.service
● apache2.service - The Apache HTTP Server
   Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
  Drop-In: /lib/systemd/system/apache2.service.d
           └─apache2-systemd.conf
   Active: active (running) since Sun 2020-04-26 14:58:53 MDT; 17s ago
  Process: 32214 ExecStop=/usr/sbin/apachectl stop (code=exited, status=0/SUCCESS)
  Process: 32242 ExecStart=/usr/sbin/apachectl start (code=exited, status=0/SUCCESS)
 Main PID: 32262 (apache2)
    Tasks: 55 (limit: 4915)
   CGroup: /system.slice/apache2.service
           ├─32262 /usr/sbin/apache2 -k start
           ├─32264 /usr/sbin/apache2 -k start
           └─32265 /usr/sbin/apache2 -k start

If you run the firewall, remember to allow incoming pages to apache webserver.
$ sudo ufw enable
$ sudo ufw allow www

Saturday, April 18, 2020

Install Raspbian on Raspberry Pi B+

This will guide you through installation and configuration of a Raspberry Pi B+ with the Raspbian operating system so the device will be accessible on your network. Readily available for around $35, the Raspberry Pi ecosystem is fast-becoming a hobbyist workhorse.


Download Raspbian zip file from www.raspberrypi.org/downloads/raspbian. This example uses "Raspbian Buster with desktop" of February 2020.

Download the Etcher program from www.balena.io/etcher.  Etcher will write the OS zip file image to the SD card.

Insert an 8 GB (or more) microSD card in to the card reader on your Windows PC. This example uses a 32 GB card. In Windows Explorer you should see the SD card.
















Use the Etcher program to write the zip file OS image to the SD card.
 






























After writing the image, the SD card will be unmounted. Physically eject the card from your PC, then reinsert it. Determine the drive letter by looking in File Explorer.
















Let's tell the OS image to allow ssh login. Press the Windows Start button, type
cmd
and start the Command Prompt application.
In the command prompt, go to the drive letter of the SD card. In this example, type
F:

























Create a zero length file named ssh. In the command prompt, type
type nul > ssh



























If you will use a hard-wired ethernet connection from the device to your router, you will not need to configure wifi. To configure wifi, create a file named "wpa_supplicant.conf" with your wifi connection information. The file should only have the suffix ".conf" and the contents should not have Windows-like newline characters. It is important that newline characters are not added to this file. It should be a plain text file. Add the following to the wpa_supplicant.conf file.
country=US
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
scan_ssid=1
ssid="yourWifiSsid"
psk="yourWifiPassword"
}


Type exit to leave the command prompt.

In Windows File Explorer, right-click on the drive and choose EJECT. Physically eject the SD card from the PC.

Plug in the microSD card to the device, and insert the power connector cord in to the device. Don't yet plug it in to power.

Open your router configuration page, and look for the area which shows the current connections. You will looking for either a new DHCP client or a new MAC address. Now that you have opened your router configuration to the appropriate page, plug in the wall power for the device and turn on the power  switch.
Watch the router page for a new connection. If using wifi and it doesn't connect to the router, use the ethernet cable method. Note the IP address.


















Press the Windows Start button and open a command prompt. In the Windows command prompt, connect to the device using the IP address as seen in your router.
ssh pi@192.168.1.101
Accept the key fingerprint warning by typing yes.
The password is
raspberry

You should be logged in. Change the password.
$ passwd

















Modify settings such as locale language, host name, and maybe enable VNC. Start the handy configuration tool. I changed the locale and the host name.
$ sudo raspi-config

If wifi didn't work or you want to enable it, become root and edit the file.
$ sudo su
$ sudo vi /etc/wpa_supplicant/wpa_supplicant.conf


Reboot the device.
$ sudo reboot

The router page will show the new host name.

















For installation of an operating system on bare hardware, this was a smooth and pleasant experience. The teams who put together the custom OS and configuration tools have done superb!

Another good guide for how to install Raspbian OS is at Tom's Hardware.