This page shows how to use kubectl port-forward
to connect to a Redis
server running in a Kubernetes cluster. This type of connection can be useful
for database debugging.
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube, or you can use one of these Kubernetes playgrounds:
To check the version, enter kubectl version
.
Create a Redis deployment:
kubectl create -f https://k8s.io/examples/application/guestbook/redis-master-deployment.yaml
The output of a successful command verifies that the deployment was created:
deployment.apps/redis-master created
View the pod status to check that it is ready:
kubectl get pods
The output displays the pod created:
NAME READY STATUS RESTARTS AGE
redis-master-765d459796-258hz 1/1 Running 0 50s
View the deployment status:
kubectl get deployment
The output displays that the deployment was created:
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
redis-master 1 1 1 1 55s
View the replicaset status using:
kubectl get rs
The output displays that the replicaset was created:
NAME DESIRED CURRENT READY AGE
redis-master-765d459796 1 1 1 1m
Create a Redis service:
kubectl create -f https://k8s.io/examples/application/guestbook/redis-master-service.yaml
The output of a successful command verifies that the service was created:
service/redis-master created
Check the service created:
kubectl get svc | grep redis
The output displays the service created:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
redis-master ClusterIP 10.0.0.213 <none> 6379/TCP 27s
Verify that the Redis server is running in the pod and listening on port 6379:
kubectl get pods redis-master-765d459796-258hz --template='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
The output displays the port:
6379
kubectl port-forward
allows using resource name, such as a service name, to select a matching pod to port forward to since Kubernetes v1.10.
kubectl port-forward redis-master-765d459796-258hz 6379:6379
which is the same as
kubectl port-forward pods/redis-master-765d459796-258hz 6379:6379
or
kubectl port-forward deployment/redis-master 6379:6379
or
kubectl port-forward rs/redis-master 6379:6379
or
kubectl port-forward svc/redis-master 6379:6379
Any of the above commands works. The output is similar to this:
I0710 14:43:38.274550 3655 portforward.go:225] Forwarding from 127.0.0.1:6379 -> 6379
I0710 14:43:38.274797 3655 portforward.go:225] Forwarding from [::1]:6379 -> 6379
Start the Redis command line interface:
redis-cli
At the Redis command line prompt, enter the ping
command:
127.0.0.1:6379>ping
A successful ping request returns PONG.
Connections made to local port 6379 are forwarded to port 6379 of the pod that is running the Redis server. With this connection in place you can use your local workstation to debug the database that is running in the pod.
Warning: Due to known limitations, port forward today only works for TCP protocol. The support to UDP protocol is being tracked in issue 47862.
Learn more about kubectl port-forward.
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