README.md

README

Demonstrate how to use docker compose v2.

Other examples using Compose:

• 03_ffprobe docker-compose.yaml
• 07_coredns_tcpdump [docker-compose.yaml]https://github.com/chrisguest75/sysadmin_examples/blob/master/07_coredns_tcpdump/docker-compose.yaml)
• 44_reverse_proxy README.md

Demonstrates:

• Building and naming images
• Networks

TODO:

• Build docker compose --env-file ./compose.env -f ./docker-compose-tests.yaml --profile backend build --force-rm --no-cache
• https://docs.docker.com/compose/extends/

NOTES:

• --ssh is not supported on compose. You have to build image seperately.
• Docker Compose V2 is a plugin. This can be installed on apt using apt-get install -qq -y docker-compose-plugin - follow guide here

Build & Run

# show the profiles
docker compose config --profiles  

# NOTE: It seems you need to purge the cache as force-recreate uses cached layers.
docker builder prune 
docker system prune --all --force 

# bring up all profiles
docker compose --env-file ./compose.env --profile all up -d --build --force-recreate
docker compose ps 

# bring up profiles individually
docker compose --profile backend up -d --build --force-recreate
docker compose --profile frontend up -d --build --force-recreate
docker compose --profile timeout up -d --build --force-recreate

# bring both profiles down
docker compose --profile backend --profile frontend down

# bring up both profiles with --build
docker compose --profile backend --profile frontend --profile timeout up -d --build --force-recreate 

# test the nginx service
curl -vv 0.0.0.0:8080         

Running Containers

# output full object as json 
docker compose ps --format json | jq              

# show containers
docker compose ps 

# show service names only 
docker compose --profile all ps --services  

Check running status

Status can be defined as one of created, restarting, running, removing, paused, exited, or dead

# has a container exited?
docker compose ps --status exited --services | grep "timeout"

# a function to detect if a container is running or not
function has_container_exited() {
    local service=$1
    docker compose ps --format json | jq -e --arg service "$service" -r '.[] | select(.Service==$service and .State=="exited")' > /dev/null
    local exitcode=$?
    if [[ $exitcode == 0 ]]; then
        echo "$1 has exited"
        return 1
    else
        echo "$1 has not exited"
        return 0
    fi
}
has_container_exited "timeout"; echo $?
has_container_exited "nginx"; echo $?
has_container_exited "ubuntu"; echo $?
has_container_exited "doesnotexist"; echo $?

Exec into running containers

# see the environment variables passed in
docker compose exec -it ubuntu env  

# exec into container and run a process
docker compose exec ubuntu ls -la /
docker compose exec -it ubuntu ls -la /   
docker compose exec -it ubuntu ls -la /root  

# create a file in containers
docker compose exec -it ubuntu touch /root/test.txt

# check file existence
docker compose exec -it ubuntu bash -c "[[ -f /root/test.txt ]] && echo 'This file exists!'"
docker compose exec -it ubuntu bash -c "[[ -f /root/test.txt ]] && exit 1"
echo "$? exitcode"

# shell into container
docker compose exec -it ubuntu bash      

Logs

# quick test of logs
docker compose logs ubuntu
docker compose logs nginx
docker compose logs timeout

Docker Compose Helper

# check status ubuntu
./docker-compose-helper.sh --action=check --service=ubuntu --file=./docker-compose.yaml --envfile=./compose.env

# check name timeout
./docker-compose-helper.sh --action=name --service=timeout --file=./docker-compose.yaml --envfile=./compose.env

# wait for nginx
/docker-compose-helper.sh --action=wait --service=nginx --file=./docker-compose.yaml --envfile=./compose.env

Cleanup

# bring it down and delete the volume
docker compose --env-file ./compose.env --profile all down --volumes

Resources

• Compose Spec Site here
• The Compose Specification here
• docker ps here
• Awesome Compose here