Update 2021-01-08: this is now out of date. See my updated post with a much easier method.

I have a number of Ubiquiti UAPs, and I manage them with the UniFi app, installed on a linode server. Like any publicly hosted server, i want to use a trusted SSL certificate, and for that, I chose LetsEncrypt with DNS-01 validation, as i found a useful helper script by thatsamguy on the UniFi forums. I use AWS Route53 to host the DNS zone.

1. go to VMware ESXi Patch Tracker and check for the latest ImageProfile e.g. ESXi-6.5.0-20170404001-standard
2. Shut down all VMs and turn on maintenance mode
3. allow outbound firewall requests
   esxcli network firewall ruleset set -e true -r httpClient
4. execute the update:
   esxcli software profile update -p ESXi-6.5.0-20170404001-standard -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml
5. Disable firewall ports
   esxcli network firewall ruleset set -e false -r httpClient
6. Disable maintenance mode
7. Reboot

Some of my docker containers were complaining that they didn’t have enough drive space. This looked odd - so i logged in to the host and checked around:

robert@d:/$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 2.0G 0 2.0G 0% /dev
tmpfs 394M 12M 382M 3% /run
/dev/sda1 26G 25G 0 100% /
tmpfs 2.0G 2.0M 2.0G 1% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 2.0G 0 2.0G 0% /sys/fs/cgroup
//fs.cynexia.net/largeappdata 2.7T 285G 2.4T 11% /mnt/largeappdata
//fs.cynexia.net/video 5.4T 3.0T 2.4T 56% /mnt/video
//fs.cynexia.net/appdata 2.5T 52G 2.4T 3% /mnt/appdata

All space used up. Huh. Wonder why? I did a quick check to see what’s using most space:

onwards…

1. downloaded the Ubuntu 16.04 Server LTS CD
2. Created new VM
3. Connected ISO to virtual DVD in console in VMWare vSphere client
4. booted to the ISO
5. pressed F4 and selected “minimal”
6. pressed F6 and selected minimal VM
7. walked through and added SSH at the right point
8. SSHd to the server
9. I installed docker using these instructions, including configuring docker to start on boot.
10. created /mnt/cups
11. ran a new docker container… robert@ubd:/mnt$ sudo docker run -d –name=“cups-google-print” –net=“host” –privileged=“true” -e TZ=“UTC” -e HOST_OS=“ubuntu” -e “CUPS_USER_ADMIN”=“admin” -e “CUPS_USER_PASSWORD”=“pass” -e “TCP_PORT_631”=“631” -v “/mnt/cups”:"/config":rw -v /dev:/dev -v /etc/avahi/services:/avahi -v /var/run/dbus:/var/run/dbus mnbf9rca/cups-google-print –restart=unless-stopped Unable to find image ‘mnbf9rca/cups-google-print:latest’ locally latest: Pulling from mnbf9rca/cups-google-print a3ed95caeb02: Pull complete 3b1d42cd9af9: Pull complete d2ff49536f4d: Pull complete f94adccdbb9c: Pull complete ae857e8dd13c: Pull complete 327565847940: Pull complete 83835dcb6373: Pull complete 78b26d55dd43: Pull complete 388ec0e358c7: Extracting [=======================================> ] 190 MB/238.1 MB 388ec0e358c7: Pull complete 05dd908ba895: Pull complete 87c9e1d25f3b: Pull complete 75d49e6da022: Pull complete 4b8ca4d5d690: Pull complete Digest: sha256:3c231589c941288c4541016944658ee5915e4d8761648e1d88254c90dea9beca Status: Downloaded newer image for mnbf9rca/cups-google-print:latest f33434ebccaf2b5644260e664014d7364d4d5ead45bf4374e931a0acedd06015
12. checked it’s running with the docker ps -a command: robert@ubd:/mnt$ sudo docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES f33434ebccaf mnbf9rca/cups-google-print “/sbin/my_init” 2 minutes ago Up 2 minutes cups-google-print
13. Browsed to https://<server IP>:631/ to see that it’s running

bingo!