2023 - January
Docker
Docker is a way to manage containers, which are like namespaces or jails. Here are some useful common commands to check out the status of these containers.
Prune unused containers, images and cache
This can free up disk space.
$ docker system prune
WARNING! This will remove:
- all stopped containers
- all networks not used by at least one container
- all dangling images
- all dangling build cache
Are you sure you want to continue? [y/N] y
Deleted Containers:
e91363806fd869a4f9349fc2de4faf26cc6b4b26a7fdbf16c5535c13ef46f995
Deleted Images:
untagged: homeassistant/home-assistant@sha256:1b4a62627444841ad222aaf3795b90581c2f8b712762c8d7d6b6cf9a42045ea8
deleted: sha256:8a975b58aacfc196fbe3eeb34810b9068e8a50d953ff88b67504d1c2351940d7
deleted: sha256:8df0a83f8a5a8360e6deef1187b2dbf6c27b7fe57584bca0b657671363a20729
deleted: sha256:abdac85af7ebbecf80442d554fa655133eb4ee2dbf4d96136caf1615e7f82992
deleted: sha256:b992bfbe5047c28682b5cc7ce976e418b5402113ee404143a4de208214f322f7
deleted: sha256:84e4d6e3db7ee758f3089b2f28ed3b1d248e31c72604004fdfdd34970c1a47
...
Total reclaimed space: 3.556GB
Reference: https://docs.docker.com/engine/reference/commandline/system_prune/
Check a container's logs
$ docker logs -f homeassistant
...
Traceback (most recent call last):
File "/usr/local/lib/python3.10/site-packages/pyatv/protocols/airplay/__init__.py", line 258, in _connect_rc
await control.start(str(core.config.address), control_port, credentials)
File "/usr/local/lib/python3.10/site-packages/pyatv/protocols/airplay/remote_control.py", line 60, in start
await self._setup_event_channel(self.connection.remote_ip)
File "/usr/local/lib/python3.10/site-packages/pyatv/protocols/airplay/remote_control.py", line 102, in _setup_event_channel
resp = await self._setup(
...
Inspect a container
$ docker container inspect homeassistant
[
{
"Id": "0baa0742e18858ebea97a93ee5a97f0fb09f369d504d3f6d1252c8c35234ac91",
"Created": "2023-04-16T23:45:06.042429674Z",
"Path": "/init",
"Args": [],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 2378698,
"ExitCode": 0,
"Error": "",
"StartedAt": "2023-04-16T23:45:06.981493189Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
...
Check for container filesystem changes since start
$ docker diff <container name>
Check container running processes
$ docker top homeassistant
UID PID PPID C STIME TTY TIME CMD
root 2378698 2378670 0 19:45 ? 00:00:00 /package/admin/s6/command/s6-svscan -d4 -- /run/service
root 2378732 2378698 0 19:45 ? 00:00:00 s6-supervise s6-linux-init-shutdownd
root 2378733 2378732 0 19:45 ? 00:00:00 /package/admin/s6-linux-init/command/s6-linux-init-shutdownd -c /run/s6/basedir -g 3000 -C -B
root 2378742 2378698 0 19:45 ? 00:00:00 s6-supervise s6rc-fdholder
root 2378743 2378698 0 19:45 ? 00:00:00 s6-supervise s6rc-oneshot-runner
root 2378751 2378743 0 19:45 ? 00:00:00 /package/admin/s6/command/s6-ipcserverd -1 -- /package/admin/s6/command/s6-ipcserver-access -v0 -E -l0 -i data/rules -- /package/admin/s6/command/s6-sudod -t 30000 -- /package/admin/s6-rc/command/s6-rc-oneshot-run -l ../.. --
root 2378782 2378698 0 19:45 ? 00:00:00 s6-supervise home-assistant
root 2378784 2378782 1 19:45 ? 00:00:15 python3 -m homeassistant --config /config
Check container statistics
$ docker stats homeassistant
CONTAINER ID NAME CPU % MEM USAGE / LIMIT MEM % NET I/O BLOCK I/O PIDS
0baa0742e188 homeassistant 0.23% 217.6MiB / 15.52GiB 1.37% 0B / 0B 102MB / 10.5MB 21
Check docker networks
$ docker network ls
NETWORK ID NAME DRIVER SCOPE
b67081eb628c bridge bridge local
0921bc6a0760 host host local
c8363d03e4cd none null local
$ docker network inspect bridge
[
{
"Name": "bridge",
"Id": "b67081eb628c51d90d2f234df1c97580bc0d83fa52c300f2fbf4764556a14ba6",
"Created": "2023-04-15T06:02:48.923361812-04:00",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "172.17.0.0/16",
"Gateway": "172.17.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"3357239a67204620012173ae3cd724a2508d9456d2aaabee7b1be3d7b351e6f7": {
"Name": "zwave-js",
"EndpointID": "7d50227167937e8ce5886abeb87411f66902eae494b4b3860ec133b77a39ecbd",
"MacAddress": "02:42:ac:11:00:02",
"IPv4Address": "172.17.0.2/16",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.bridge.default_bridge": "true",
"com.docker.network.bridge.enable_icc": "true",
"com.docker.network.bridge.enable_ip_masquerade": "true",
"com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
"com.docker.network.bridge.name": "docker0",
"com.docker.network.driver.mtu": "1500"
},
"Labels": {}
}
]
Move data files
Default docker installs will put the large containers into /var/lib/docker which may be a directory off root. It is better to put them on a seperate filesystem in case they grow unexpectedly.
1 - Stop the docker daemon
sudo service docker stop
2 - Add a configuration file to tell the docker daemon what is the location of the data directory
Change the data-root location:
File: /etc/docker/daemon.json
{
"data-root": "/path/to/your/docker"
}
3 - Copy the current data directory to the new one
sudo rsync -aP /var/lib/docker/ /path/to/your/docker
4 - Rename the old docker directory
sudo mv /var/lib/docker /var/lib/docker.old
This is just a sanity check to see that everything is ok and docker daemon will effectively use the new location for its data.
5 - Restart the docker daemon
sudo service docker start
6 - Test
If everything is ok you should see no differences in using your docker containers. When you are sure that the new directory is being used correctly by docker daemon you can delete the old data directory.
sudo rm -rf /var/lib/docker.old
Upgrade a container
Here is my documentation on upgrading the homeassistant docker container:
January - Docker - Linux in the House - https://linux-in-the-house.org
