Deploy docker containers using GitOps approach

If you were searching for the tool like ArgoCD to implement GitOps pattern for Docker containers - you are on the right place.

Simplecontainer enables the GitOps approach to deploying containers on single or cluster of docker daemon hosts with simplecontainer enabled nodes.

This allows to pull the latest changes on the definitions from the git repository instead of pushing the changes to the node via CLI.

To checkout gitops deployment - first, you need to have simplecontainer running and CLI configured already. If you didn't do that you need to do that first.

simplecontainer

Simplecontainer manager a.k.a smr. Standalone and cluster mode, GitOps, Secrets, Reconciliation, and YAML definitions for Docker.

Afterward, clone the examples repository and list the definitions inside the directories.

git clone https://github.com/simplecontainer/examples

GitOps manual sync for simplecontainer

An example definition of the GitOps object is given below.

kind: gitops
meta:
  group: examples
  name: plain-manual
spec:
  repoURL: "https://github.com/simplecontainer/examples"
  revision: "main"
  directoryPath: "/tests/minimal"

Applying this object: examples/tests/gitops-apps/gitops-manual.yaml simplecontainer willl create an GitOps object on the node and will reconcile all definitions specified under the directoryPath on the revision of the git repository.

smr apply examples/tests/gitops-apps/definitions/gitops-plain.yaml
everything went smoothly: good job!

smr ps gitops
RESOURCE                             REPOSITORY                                             REVISION  SYNCED        AUTO   STATE    STATUS              
gitops/examples/plain-manual         https://github.com/simplecontainer/examples (eae4c94)  main      Never synced  false  Drifted  definitionsinvalid  

A GitOps object can do auto sync and manual sync. Since the sync is manual in this case we need to trigger the sync manually via CLI.

smr gitops sync examples plain-manual
smr ps
NODE         RESOURCE                              PORTS  DEPS  ENGINE STATE      SMR STATE      
smr-agent-2  containers/example/example-busybox-1  -      -     running (docker)  running (53s)  
smr-agent-2  containers/example/example-busybox-2  -      -     running (docker)  running (53s)  

Simplecontainer will pick up definitions from the definition.yaml and will reconcile the state - create containers on the node.

GitOps auto sync for simplecontainer

kind: gitops
meta:
  group: examples
  name: plain-auto
spec:
  repoURL: "https://github.com/simplecontainer/examples"
  revision: "main"
  automaticSync: true
  directoryPath: "/tests/minimal"

After applying this object it will auto-sync changes.

GitOps App of apps pattern for simplecontainer

kind: gitops
meta:
  group: examples
  name: app-of-apps
spec:
  repoURL: "https://github.com/simplecontainer/examples"
  revision: "main"
  directoryPath: "tests/gitops-apps"

Using this pattern we can create one GitOps object that will automate creation and syncing of new GitOps objects.

smr apply examples/tests/gitops-app-of-apps.yaml
everything went smoothly: good job!

smr gitops sync examples app-of-apps
sync is triggered manually

RESOURCE                             REPOSITORY                                             REVISION  SYNCED        AUTO   STATE    STATUS              
gitops/examples/app-of-apps          https://github.com/simplecontainer/examples (eae4c94)  main      eae4c94       false  InSync   insync              
gitops/examples/plain-auto           https://github.com/simplecontainer/examples (eae4c94)  main      eae4c94       true   InSync   insync              
gitops/examples/plain-manual         https://github.com/simplecontainer/examples (eae4c94)  main      Never synced  false  Drifted  definitionsinvalid  
gitops/examples/plain-manual-spread  https://github.com/simplecontainer/examples (eae4c94)  main      Never synced  false  Drifted  definitionsinvalid  

smr ps
NODE         RESOURCE                              PORTS  DEPS  ENGINE STATE      SMR STATE      
smr-agent-2  containers/example/example-busybox-1  -      -     running (docker)  running (53s)  
smr-agent-2  containers/example/example-busybox-2  -      -     running (docker)  running (53s)  

As you can see after syncing app-of-apps GitOps object it will create the rest of the GitOps objects from /tests/gitops/apps directory.

Using dashboard we can investigate in the real time what is happening to the GitOps objects and what they hold inside. For this example in particular the output would be similar to the one in the video below.