> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Solution Pods optional
> This lab teaches working with Pods in Kubernetes using imperative commands and declarative YAML configurations, including creation, inspection, troubleshooting, and updates.
In this lab, you will learn how to work with Pods in Kubernetes using both imperative commands and declarative YAML configurations. The lab covers checking existing Pods, creating new Pods with different images, inspecting their details, troubleshooting common errors, and updating configurations to fix issues.
***
## Listing Existing Pods
Start by listing the Pods in your default namespace. This step helps you verify that no unexpected Pods are running before you begin:
```bash theme={null}
kubectl get pods
```
If no Pods are running, the output will look similar to:
```bash theme={null}
controlplane ~ ⟫ kubectl get pods
No resources found in default namespace.
controlplane ~ ⟫
```
***
## Creating a New Pod with the nginx Image
Next, create a new Pod that uses the nginx image by executing:
```bash theme={null}
kubectl run nginx --image=nginx
```
The output should confirm the creation of the Pod:
```bash theme={null}
kubectl run nginx --image=nginx
pod/nginx created
```
Verify the creation by listing the Pods again:
```bash theme={null}
kubectl get pods
```
You may see multiple Pods, especially if you have done previous exercises. For example:
```bash theme={null}
controlplane ~ ➜ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx 0/1 ContainerCreating 0 17s
newpods-llstt 0/1 ContainerCreating 0 11s
newpods-pnnx8 0/1 ContainerCreating 0 11s
newpods-k87fx 0/1 ContainerCreating 0 11s
```
Some Pods might still display "ContainerCreating" as they are in the process of being set up.
***
## Inspecting Pod Details and Verifying the Image
To inspect the details of a specific Pod and verify which image is used, run:
```bash theme={null}
kubectl describe pod
```
For example, the detailed output may include:
```text theme={null}
Node: controlplane/172.25.0.47
Start Time: Fri, 15 Apr 2022 18:12:04 +0000
Labels: tier=busybox
...
Containers:
busybox:
Container ID: containerd://b05cd692af1f3b433883f9a8ece19ec2e8c4fcf861aa97ae6a82857ed6037a6d
Image: busybox
Image ID: docker.io/library/busybox@sha256:d2b533584f580310186df7a2055ce3ff83cc0df6caacf1e3489bf
Command:
sleep
1000
State: Running
...
```
In this excerpt, the image used is **busybox**. You can also use the wide output option to display node information:
```bash theme={null}
kubectl get pods -o wide
```
The output might be:
```bash theme={null}
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READY
newpods-pnnx8 1/1 Running 0 2m3s 10.42.0.10 controlplane
newpods-llstt 1/1 Running 0 2m3s 10.42.0.12 controlplane
newpods-k87fx 1/1 Running 0 2m3s 10.42.0.11 controlplane
nginx 1/1 Running 0 2m9s 10.42.0.9 controlplane
```
***
## Working with a Multi-Container Pod
Consider a Pod named `webapp` that contains two containers. To view the details of this multi-container Pod, run:
```bash theme={null}
kubectl describe pod webapp
```
A sample excerpt from the description might show:
```bash theme={null}
Priority: 0
Node: controlplane/172.25.0.47
Start Time: Fri, 15 Apr 2022 18:14:22 +0000
...
Containers:
nginx:
Container ID: containerd://42fc9932fb07a3047ea1902a6255e75139e981a37426e0d31ea5ec7a833481d
Image: nginx
State: Running
Ready: True
Restart Count: 0
...
agentx:
Container ID: agentx
Image: agentx
State: Waiting
Reason: ErrImagePull
Ready: False
Restart Count: 0
...
```
In this Pod, the **nginx** container is running normally, while the **agentx** container is in a waiting state due to an image pull error (ErrImagePull). When you list the Pods, observe that the READY column indicates the number of ready containers versus the total containers:
```bash theme={null}
kubectl get pods
NAME READY STATUS RESTARTS AGE
newpods-pnnx8 1/1 Running 0 2m33s
newpods-llstt 1/1 Running 0 2m33s
newpods-k87fx 1/1 Running 0 2m33s
nginx 1/1 Running 0 2m39s
webapp 0/1 ImagePullBackOff 0 15s
```
The `ErrImagePull` error indicates that Kubernetes failed to pull the image for the **agentx** container, likely because the image name is incorrect or the image does not exist on Docker Hub.
***
## Deleting the Erroneous Web App Pod
Since the `webapp` Pod contains an image pull error, remove it by running:
```bash theme={null}
kubectl delete pod webapp
```
You should see a deletion confirmation:
```bash theme={null}
pod "webapp" deleted
```
***
## Creating and Correcting a Redis Pod
Now, create a new Pod named `redis` using an intentionally incorrect image name (`redis123`). This exercise demonstrates how to use declarative YAML and fix common errors.
### Step 1: Create the YAML File
Generate the Pod definition using a dry run:
```bash theme={null}
kubectl run redis --image=redis123 --dry-run=client -o yaml
```
Redirect the output to a file named `redis.yaml`. The file should resemble:
```yaml theme={null}
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: redis
name: redis
spec:
containers:
- image: redis123
name: redis
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
```
### Step 2: Create the Redis Pod
Apply the YAML file to create the Pod:
```bash theme={null}
kubectl create -f redis.yaml
```
The expected output is:
```bash theme={null}
pod/redis created
```
Verify the Pod status:
```bash theme={null}
kubectl get pods
```
The output may look like:
```bash theme={null}
NAME READY STATUS RESTARTS AGE
newpods-pnnx8 1/1 Running 0 8m16s
newpods-llstt 1/1 Running 0 8m16s
newpods-k87fx 1/1 Running 0 8m16s
nginx 1/1 Running 0 8m22s
redis 0/1 ErrImagePull 0 10s
```
Since the image name `redis123` is invalid, the Pod enters an `ErrImagePull` state.
### Step 3: Update the YAML File with the Correct Image
Edit the `redis.yaml` file to update the image name from `redis123` to `redis`. The updated file should be:
```yaml theme={null}
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: redis
name: redis
spec:
containers:
- image: redis
name: redis
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
```
Apply the changes with:
```bash theme={null}
kubectl apply -f redis.yaml
```
You might see a warning indicating that the Pod is missing an annotation necessary for future apply operations. After updating, verify the status again:
```bash theme={null}
kubectl get pods
```
An example output is:
```bash theme={null}
NAME READY STATUS RESTARTS AGE
newpods-pnnx8 1/1 Running 0 9m38s
newpods-llstt 1/1 Running 0 9m38s
newpods-k87fx 1/1 Running 0 9m44s
nginx 1/1 Running 0 9m44s
redis 1/1 Running 0 92s
```
The `redis` Pod is now running correctly thanks to the valid Docker image.
***
## Conclusion
In this lab, you learned how to:
* List existing Pods in a Kubernetes cluster.
* Create new Pods using imperative commands with different images.
* Inspect detailed information about Pods to verify configurations.
* Troubleshoot common issues like image pull errors.
* Use declarative YAML configurations to manage and update Pods.
Happy clustering and keep exploring more Kubernetes features!