This is a documentation that I made when I implemented GlusterFS into Docker as the container storage solution. It is also a continuation of this previous post as well.
The setup that I used include: 3 Debian 10 VMs with an extra hard disk/drive each and Docker installed with Docker Swarm enabled.
Install the GlusterFS Docker plugin (on all three nodes)
sudo docker plugin install –alias glusterfs trajano/glusterfs-volume-plugin –grant-all-permissions –disable
Set the Gluster servers and enable the plugin (on all three nodes)
sudo docker plugin set glusterfs SERVERS=192.168.5.25,192.168.5.26,192.168.5.27
sudo docker plugin enable glusterfs
Create a subdirectory inside the mounted Gluster volume directory (on the main node)
sudo mkdir -p /mnt/vol1
Create docker-compose.yml to test a simple service
sudo nano docker-compose.yml
| version: “3.4” services: foo: image: alpine command: ping localhost networks: – net volumes: – vol1:/tmp networks: net: driver: overlay volumes: vol1: driver: glusterfs name: “gfs/vol1” |
Deploy the stack
sudo docker stack deploy -c docker-compose.yml test
sudo docker service ls
sudo docker service ps test_foo
Verification (on the node the container is running on)
sudo docker volume ls
Exec into the container and look at the disk layout:
sudo docker ps
sudo docker exec -it [containerID] sh
Test data persistence
create a file inside the directory that is mapped to the Gluster volume in the container:
echo $HOSTNAME > /tmp/data.txt
cat /tmp/data.txt
Scale the service to 3 replicas:
sudo docker service scale test_foo=3
sudo docker service ps test_foo
Check on another node to see if data.txt persisted
sudo docker ps
sudo docker exec -it [containerID] sh
cat /tmp/data.txt
Append data.txt again and remove the stack
echo $HOSTNAME >> /tmp/data.txt
cat /tmp/data.txt
sudo docker stack rm test
Deploy the stack again
sudo docker stack deploy -c docker-compose.yml test
sudo docker service ps test_foo
Verify that data.txt persisted on the node that the container is on
docker exec -it [containerID] cat /tmp/data.txt
The data is replicated and stored in the VM itself as well
