mirror of https://github.com/k3s-io/k3s
Delete the dreaded CR character.
Eric Tune
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#Connecting to applications: kubectl port-forward
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kubectl port-forward forwards connections to a local port to a port on a pod. Its man page is available [here](../../docs/kubectl_port-forward.md). Compared to [kubectl proxy](../../docs/accessing-the-cluster.md#using-kubectl-proxy), `kubectl port-forward` is more generic as it can forward TCP traffic while `kubectl proxy` can only forward HTTP traffic. This guide demonstrates how to use `kubectl port-forward` to connect to a Redis database, which may be useful for database debugging.
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## Creating a Redis master
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```
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$kubectl create examples/redis/redis-master.yaml
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pods/redis-master
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```
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wait until the Redis master pod is Running and Ready,
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```
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$ kubectl get pods
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NAME READY STATUS RESTARTS AGE
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redis-master 2/2 Running 0 41s
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```
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## Connecting to the Redis master[a]
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The Redis master is listening on port 6397, to verify this,
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```
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$ kubectl get pods redis-master -t='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
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6379
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```
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then we forward the port 6379 on the local workstation to the port 6379 of pod redis-master,
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```
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$ kubectl port-forward -p redis-master 6379:6379
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I0710 14:43:38.274550 3655 portforward.go:225] Forwarding from 127.0.0.1:6379 -> 6379
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I0710 14:43:38.274797 3655 portforward.go:225] Forwarding from [::1]:6379 -> 6379
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```
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To verify the connection is successful, we run a redis-cli on the local workstation,
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```
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$ redis-cli
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127.0.0.1:6379> ping
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PONG
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```
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Now one can debug the database from the local workstation.
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#Connecting to applications: kubectl port-forward
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kubectl port-forward forwards connections to a local port to a port on a pod. Its man page is available [here](../../docs/kubectl_port-forward.md). Compared to [kubectl proxy](../../docs/accessing-the-cluster.md#using-kubectl-proxy), `kubectl port-forward` is more generic as it can forward TCP traffic while `kubectl proxy` can only forward HTTP traffic. This guide demonstrates how to use `kubectl port-forward` to connect to a Redis database, which may be useful for database debugging.
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## Creating a Redis master
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```
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$kubectl create examples/redis/redis-master.yaml
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pods/redis-master
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```
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wait until the Redis master pod is Running and Ready,
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```
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$ kubectl get pods
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NAME READY STATUS RESTARTS AGE
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redis-master 2/2 Running 0 41s
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```
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## Connecting to the Redis master[a]
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The Redis master is listening on port 6397, to verify this,
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```
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$ kubectl get pods redis-master -t='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
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6379
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```
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then we forward the port 6379 on the local workstation to the port 6379 of pod redis-master,
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```
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$ kubectl port-forward -p redis-master 6379:6379
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I0710 14:43:38.274550 3655 portforward.go:225] Forwarding from 127.0.0.1:6379 -> 6379
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I0710 14:43:38.274797 3655 portforward.go:225] Forwarding from [::1]:6379 -> 6379
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```
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To verify the connection is successful, we run a redis-cli on the local workstation,
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```
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$ redis-cli
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127.0.0.1:6379> ping
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PONG
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```
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Now one can debug the database from the local workstation.
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[]()
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@ -1,22 +1,22 @@
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#Connecting to applications: kubectl proxy and apiserver proxy
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You have seen the [basics](../../docs/accessing-the-cluster.md) about `kubectl proxy` and `apiserver proxy`. This guide shows how to use them together to access a service([kube-ui](../../docs/ui.md)) running on the Kubernetes cluster from your workstation.
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##Getting the apiserver proxy URL of kube-ui
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kube-ui is deployed as a cluster add-on. To find its apiserver proxy URL,
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```
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$ kubectl cluster-info | grep "KubeUI"
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KubeUI is running at https://173.255.119.104/api/v1/proxy/namespaces/kube-system/services/kube-ui
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```
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if this command does not find the URL, try the steps [here](../../docs/ui.md#accessing-the-ui).
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##Connecting to the kube-ui service from your local workstation
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The above proxy URL is an access to the kube-ui service provided by the apiserver. To access it, you still need to authenticate to the apiserver. `kubectl proxy` can handle the authentication.
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```
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$ kubectl proxy --port=8001
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Starting to serve on localhost:8001
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```
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#Connecting to applications: kubectl proxy and apiserver proxy
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You have seen the [basics](../../docs/accessing-the-cluster.md) about `kubectl proxy` and `apiserver proxy`. This guide shows how to use them together to access a service([kube-ui](../../docs/ui.md)) running on the Kubernetes cluster from your workstation.
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##Getting the apiserver proxy URL of kube-ui
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kube-ui is deployed as a cluster add-on. To find its apiserver proxy URL,
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```
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$ kubectl cluster-info | grep "KubeUI"
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KubeUI is running at https://173.255.119.104/api/v1/proxy/namespaces/kube-system/services/kube-ui
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```
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if this command does not find the URL, try the steps [here](../../docs/ui.md#accessing-the-ui).
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##Connecting to the kube-ui service from your local workstation
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The above proxy URL is an access to the kube-ui service provided by the apiserver. To access it, you still need to authenticate to the apiserver. `kubectl proxy` can handle the authentication.
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```
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$ kubectl proxy --port=8001
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Starting to serve on localhost:8001
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```
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Now you can access the kube-ui service on your local workstation at [http://localhost:8001/api/v1/proxy/namespaces/kube-system/services/kube-ui](http://localhost:8001/api/v1/proxy/namespaces/kube-system/services/kube-ui)
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@ -1,49 +1,49 @@
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#Getting into containers: kubectl exec
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Developers can use `kubectl exec` to run commands in a container. This guide demonstrates two use cases.
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##Using kubectl exec to check the environment variables of a container
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Kubernetes exposes [services](../../docs/services.md#environment-variables) through environment variables. It is convenient to check these environment variables using `kubectl exec`.
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We first create a pod and a service,
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```
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$ kubectl create -f examples/guestbook/redis-master-controller.yaml
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$ kubectl create -f examples/guestbook/redis-master-service.yaml
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```
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wait until the pod is Running and Ready,
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```
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$ kubectl get pod
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NAME READY REASON RESTARTS AGE
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redis-master-ft9ex 1/1 Running 0 12s
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```
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then we can check the environment variables of the pod,
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```
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$ kubectl exec redis-master-ft9ex env
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...
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REDIS_MASTER_SERVICE_PORT=6379
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REDIS_MASTER_SERVICE_HOST=10.0.0.219
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...
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```
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We can use these environment variables in applications to find the service.
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## Using kubectl exec to check the mounted volumes
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It is convenient to use `kubectl exec` to check if the volumes are mounted as expected.
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We first create a Pod with a volume mounted at /data/redis,
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```
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kubectl create -f examples/walkthrough/pod2.yaml
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```
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wait until the pod is Running and Ready,
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```
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$ kubectl get pods
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NAME READY REASON RESTARTS AGE
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storage 1/1 Running 0 1m
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```
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we then use `kubectl exec` to verify that the volume is mounted at /data/redis,
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```
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$ kubectl exec storage ls /data
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redis
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```
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#Getting into containers: kubectl exec
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Developers can use `kubectl exec` to run commands in a container. This guide demonstrates two use cases.
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##Using kubectl exec to check the environment variables of a container
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Kubernetes exposes [services](../../docs/services.md#environment-variables) through environment variables. It is convenient to check these environment variables using `kubectl exec`.
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We first create a pod and a service,
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```
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$ kubectl create -f examples/guestbook/redis-master-controller.yaml
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$ kubectl create -f examples/guestbook/redis-master-service.yaml
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```
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wait until the pod is Running and Ready,
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```
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$ kubectl get pod
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NAME READY REASON RESTARTS AGE
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redis-master-ft9ex 1/1 Running 0 12s
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```
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then we can check the environment variables of the pod,
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```
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$ kubectl exec redis-master-ft9ex env
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...
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REDIS_MASTER_SERVICE_PORT=6379
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REDIS_MASTER_SERVICE_HOST=10.0.0.219
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...
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```
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We can use these environment variables in applications to find the service.
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## Using kubectl exec to check the mounted volumes
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It is convenient to use `kubectl exec` to check if the volumes are mounted as expected.
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We first create a Pod with a volume mounted at /data/redis,
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```
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kubectl create -f examples/walkthrough/pod2.yaml
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```
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wait until the pod is Running and Ready,
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```
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$ kubectl get pods
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NAME READY REASON RESTARTS AGE
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storage 1/1 Running 0 1m
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```
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we then use `kubectl exec` to verify that the volume is mounted at /data/redis,
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```
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$ kubectl exec storage ls /data
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redis
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```
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## Using kubectl exec to open a bash terminal in a pod
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After all, open a terminal in a pod is the most direct way to introspect the pod. Assuming the pod/storage is still running, run
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