kbg

kbg (Kube Blue-Green) - Pronounced "Cabbage"

Installation

Docker Local

# assuming local kube is running and kubectx is pointing to it
make install
docker-compose up kbg

Install in Production cluster

TODO

Workflow

Usage

~/ kubectl create ns test
namespace/test created

~/ kubectl apply -f config/samples/cluster_v1alpha1_bluegreendeployment.yaml -n test
bluegreendeployment.cluster.kbg/myserver created

~/ kubectl get kbg -n test
NAME       COLOR   STATUS    ACTIVE   BACKUP   AGE
myserver   blue    Unknown   0        0        8s

~/ kubectl get all -n test
NAME                       READY   STATUS    RESTARTS   AGE
pod/myserver-blue-6w6st    1/1     Running   0          34s
pod/myserver-blue-q4w2v    1/1     Running   0          34s
pod/myserver-green-qjfcc   1/1     Running   0          34s

NAME                      TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
service/myserver          NodePort   10.106.146.24   <none>        80:30697/TCP   34s
service/myserver-backup   NodePort   10.107.59.27    <none>        80:31623/TCP   34s

NAME                             DESIRED   CURRENT   READY   AGE
replicaset.apps/myserver-blue    2         2         2       34s
replicaset.apps/myserver-green   1         1         1       34s

~/ kubectl get kbg -n test
NAME       COLOR   STATUS    ACTIVE   BACKUP   AGE
myserver   blue    Nominal   2        1        38s

Update the Nginx version in the sample

containers:
  - name: nginx
    image: nginx:1.19.0

~/ kubectl apply -f config/samples/cluster_v1alpha1_bluegreendeployment.yaml -n test
bluegreendeployment.cluster.kbg/myserver configured

~/ kubectl get kbg -n test
NAME       COLOR   STATUS     ACTIVE   BACKUP   AGE
myserver   blue    Deploying  2        1        13m

~/ kubectl get all -n test
NAME                       READY   STATUS    RESTARTS   AGE
pod/myserver-blue-6w6st    1/1     Running   0          13m
pod/myserver-green-4nkc4   1/1     Running   0          2m21s
pod/myserver-green-x8dl7   1/1     Running   0          2m37s

NAME                      TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
service/myserver          NodePort   10.106.146.24   <none>        80:30697/TCP   13m
service/myserver-backup   NodePort   10.107.59.27    <none>        80:31623/TCP   13m

NAME                             DESIRED   CURRENT   READY   AGE
replicaset.apps/myserver-blue    1         1         1       13m
replicaset.apps/myserver-green   2         2         2       2m37s

~/ kubectl get kbg -n test
NAME       COLOR   STATUS    ACTIVE   BACKUP   AGE
myserver   green   Nominal   2        1        14m

~/ curl -sD - 127.0.0.1:30697 -o /dev/null | grep Server
Server: nginx/1.19.0

For instant rollback set these values

spec:
  swapStrategy: SwapThenScale
  overrideColor: blue 

~/ kubectl apply -f config/samples/cluster_v1alpha1_bluegreendeployment.yaml -n test
bluegreendeployment.cluster.kbg/myserver configured

~/ kubectl get kbg -n test
NAME       COLOR   STATUS       ACTIVE   BACKUP   AGE
myserver   blue    Overridden   2        1        17m

Clean up

~/ kubectl delete kbg --all -n test
bluegreendeployment.cluster.kbg "myserver" deleted

~/ kubectl get all -n test
No resources found in test namespace.

TODOs/Missing Features

• HPA support (untested)
• Default/Validating webhooks (untested)
• Sync mode (hook into admission?) to fail the update if tests fail
• RBAC, tested in "privileged" mode
• Fix all TODOs
• Unit/Integration testing, then refactoring

References

• A big part of this is based on Google's sample Blue/Green Controller
• Kubebuilder book
• Kubebuilder book v1