====== Docker ======

https://docs.docker.com/storage/volumes/

===== Main install =====
<code>
apt-get -y install curl unzip dialog
curl -fSSL get.docker.com | sh
</code>

Useful alias to exclude container overlays from the df command for use in .bashrc or .profile:
<code>
alias df='/usr/bin/df -x overlay'
</code>

===== Show logs =====

<code>
docker logs --follow <containername>
</code>


===== Build image =====

To build the docker image based on a Dockerfile in the current directory, use:
<code>
docker build .
</code>

===== Update container =====

Update docker container to latest version via docker compose:
<code>
#Single container:
docker compose pull calibre-web
docker compose up -d calibre-web
docker image prune

#Update all containers:
docker compose pull
docker compose up -d
docker image prune
</code>

===== Health Checks =====

Docker compose health checks:
https://medium.com/geekculture/how-to-successfully-implement-a-healthcheck-in-docker-compose-efced60bc08e

https://stefanjarina.gitbooks.io/docker/content/swarm-mode/healthchecks.html
===== Copying files to/from containers =====

Copying files from/to containers
<code>
docker cp dockerimage:/bla ./bla
docker cp ./bla dockerimage:/bla
</code>

===== Flatten docker image layers =====
Flatten docker image layers:
<code>
FROM yourbuildimage as build
# your existing build steps here
FROM scratch
COPY --from=build / /
CMD ["/your/start/script"]
</code>

===== Change mount points of containers =====
Change mount points of existing docker containers;

e.g. mount /home/<user-name> folder of host to the /mnt folder of the existing (not running) container.
  - stop docker container or whole docker engine <code>systemctl stop docker.service</code> 
  - Open configuration file corresponding to the stopped container, which can be found at /var/lib/docker/containers/99d...1fb/config.v2.json (may be config.json for older versions of docker). For pretty print use <code>vi <(jq . /var/lib/docker/containers/<container-ID>/config.v2.json)
Save updates to a file: :w config.v2.json
Exit vim: :q!
Update existing file: jq -c . config.v2.json > /var/lib/docker/containers/<container-ID>/config.v2.json
 </code>
  - Find MountPoints section: "MountPoints":{}.
  - Replace the contents with something like this (you can copy proper contents from another container with proper settings):<code>
"MountPoints":{"/mnt":{"Source":"/home/<user-name>","Destination":"/mnt","RW":true,"Name":"","Driver":"","Type":"bind","Propagation":"rprivate","Spec":{"Type":"bind","Source":"/home/<user-name>","Target":"/mnt"},"SkipMountpointCreation":false}}</code> or the same (formatted):<code>
  "MountPoints": {
    "/mnt": {
      "Source": "/home/<user-name>",
      "Destination": "/mnt",
      "RW": true,
      "Name": "",
      "Driver": "",
      "Type": "bind",
      "Propagation": "rprivate",
      "Spec": {
        "Type": "bind",
        "Source": "/home/<user-name>",
        "Target": "/mnt"
      },
      "SkipMountpointCreation": false
    }
  }
</code>
  - Start or restart the docker service: <code>systemctl start docker.service
service docker restart</code>
  - Start the container if necessary: <code>docker start <container-name/ID></code>


===== PHP&NGINX image =====

Containerised PHP & NGINX on Alpine, image size ~60MB:
https://levelup.gitconnected.com/containerizing-nginx-php-fpm-on-alpine-linux-953430ea6dbc
https://github.com/johnathanesanders/docker-nginx-fpm

Log nginx to stdout in Dockerfile:
<code>
# forward request and error logs to docker log collector
RUN ln -sf /dev/stdout /var/log/nginx/access.log \
	&& ln -sf /dev/stderr /var/log/nginx/error.log
</code>

===== Rename/Retag image files =====

<code>
docker tag current/image:tag new/image:tag
</code>

===== cmd shell of container =====
<code>
docker exec -it <mycontainer> bash
docker exec -it <mycontainer> /bin/sh
</code>

===== GPU hardware acceleration =====

Make sure the relevant GPU drivers are installed on the base system, then pass through the device via docker compose.
Check devices are available, there should be a device per GPU starting at renderD128 for the first GPU:
<code>
ls -la /dev/dri
</code>

<code>
  devices:
   - /dev/dri:/dev/dri
</code>

===== docker ps short =====
Short form of docker ps to only get the container names:
<code>
docker ps | sed 's/   */#/g' | cut -d "#" -f 7
</code>


===== docker command template =====
https://stackoverflow.com/questions/50667371/docker-ps-output-formatting-list-only-names-of-running-containers
===== docker running out of network addresses =====

Error response from daemon: all predefined address pools have been fully subnetted 

<code json /etc/docker/daemon.json>
{
"default-address-pools":[
    {"base":"169.254.2.0/23","size":28},
    {"base":"169.254.4.0/22","size":28},
    {"base":"169.254.8.0/21","size":28},
    {"base":"169.254.16.0/20","size":28},
    {"base":"169.254.32.0/19","size":28},
    {"base":"169.254.64.0/18","size":28},
    {"base":"169.254.128.0/18","size":28},
    {"base":"169.254.192.0/19","size":28},
    {"base":"169.254.224.0/20","size":28},
    {"base":"169.254.240.0/21","size":28},
    {"base":"169.254.248.0/22","size":28}
  ]
}
</code>
<code>
docker restart
docker network prune
</code>