Kubernetes - Documentation

Link to this headingKubernetes

Link to this headingInstall/Startup

#Kubernetes Information >>> kubectl cluster-info Kubernetes control plane is running at https://192.168.49.2:8443 CoreDNS is running at https://192.168.49.2:8443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy #Minicube Info >>> minikube profile list |----------|-----------|---------|--------------|------|---------|---------|-------|----------------|--------------------| | Profile | VM Driver | Runtime | IP | Port | Version | Status | Nodes | Active Profile | Active Kubecontext | |----------|-----------|---------|--------------|------|---------|---------|-------|----------------|--------------------| | minikube | docker | docker | 192.168.49.2 | 8443 | v1.30.0 | Running | 1 | * | * | |----------|-----------|---------|--------------|------|---------|---------|-------|----------------|--------------------| #Service Info >>> kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE myapp LoadBalancer 10.110.151.13 <pending> 8080:30306/TCP 3h43m

Pod Information:

#Pod Information >>> kubectl get pods --show-labels NAME READY STATUS RESTARTS AGE LABELS hello-world-pod 1/1 Running 0 169m <none> myapp-865648495b-gsb9z 0/1 CrashLoopBackOff 37 (64s ago) 165m app=myapp,pod-template-hash=865648495b myapp-865648495b-j7hqg 0/1 CrashLoopBackOff 37 (33s ago) 165m app=myapp,pod-template-hash=865648495b #Get Single Pod Info >>> kubectl describe pod hello-world-pod Name: hello-world-pod Namespace: myspace Priority: 0 Service Account: default Node: minikube/192.168.49.2 Start Time: Sat, 07 Sep 2024 00:05:05 +0000 Labels: <none> Annotations: <none> Status: Running IP: 10.244.0.8 IPs: IP: 10.244.0.8 Containers: hello-world-container: Container ID: docker://a5b41e190a297e935a4553ef1f47e7ae7744923eb922588cd5e6576947cc4e03 Image: nginx:latest Image ID: docker-pullable://nginx@sha256:04ba374043ccd2fc5c593885c0eacddebabd5ca375f9323666f28dfd5a9710e3 Port: <none> Host Port: <none> State: Running Started: Sat, 07 Sep 2024 00:05:11 +0000 Ready: True Restart Count: 0 Environment: <none> Mounts: /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-bz7gf (ro) Conditions: Type Status PodReadyToStartContainers True Initialized True Ready True ContainersReady True PodScheduled True Volumes: kube-api-access-bz7gf: Type: Projected (a volume that contains injected data from multiple sources) TokenExpirationSeconds: 3607 ConfigMapName: kube-root-ca.crt ConfigMapOptional: <nil> DownwardAPI: true QoS Class: BestEffort Node-Selectors: <none> Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s node.kubernetes.io/unreachable:NoExecute op=Exists for 300s Events: <none> #Get Single Service >>> kubectl describe service myapp Name: myapp Namespace: myspace Labels: app=myapp Annotations: <none> Selector: app=myapp Type: LoadBalancer IP Family Policy: SingleStack IP Families: IPv4 IP: 10.110.151.13 IPs: 10.110.151.13 Port: <unset> 8080/TCP TargetPort: 8080/TCP NodePort: <unset> 30306/TCP Endpoints: Session Affinity: None External Traffic Policy: Cluster Events: <none> #Delete Pod >>> kubectl delete pod myapp-865648495b-jbgg9 myapp-865648495b-ks9ks pod "myapp-865648495b-jbgg9" deleted pod "myapp-865648495b-ks9ks" deleted #Delete all bods by label >>> kubectl delete pod -l app=myapp pod "myapp-865648495b-gsb9z" deleted pod "myapp-865648495b-j7hqg" deleted

Namespaces:

#Create New Namespace >>> kubectl create namespace myspace namespace/myspace created #Enter new namespace >>> kubectl config set-context --current --namespace=myspace Context "minikube" modified.

Deploy new Containers:

#Create New Container >>> kubectl create deployment myapp --image=busybox:latest deployment.apps/myapp created #Scale Container >>> kubectl scale deployment myapp --replicas=2 deployment.apps/myapp scaled #Open Conter Ports to Server >>> kubectl expose deployment myapp --port 8080 --type=LoadBalancer service/myapp exposed

Link to this headingUsing YAML Files

Sample config:

apiVersion: v1 kind: Pod metadata: name: hello-world-pod spec: containers: - name: hello-world-container image: nginx:latest # command: ["echo"] # args: ["Hello World!"]

Run Config:

kubectl apply -f pod.yml

Link to this headingSecrets

Secrets are Mounted as Volumes

Secret Management:

#Add new Secret >>> kubectl create secret generic mysecret --from-literal=user="MyUserName" --from-literal=password="examplepassword" secret/mysecret created #List Secrets >>> kubectl get secrets NAME TYPE DATA AGE mysecret Opaque 2 11s #Get Secret Info >>> kubectl get secret mysecret -o yaml apiVersion: v1 data: password: ZXhhbXBsZXBhc3N3b3Jk user: TXlVc2VyTmFtZQ== kind: Secret metadata: creationTimestamp: "2024-09-07T15:50:40Z" name: mysecret namespace: myspace resourceVersion: "102386" uid: b1563310-d425-49fe-8427-32a3fa41018d type: Opaque

Link to this headingJobs

Cron Jobs

Link to this headingStern

Best way to View containers logs for all of the running instance of the same type.

All Containers with the same Pod name’s logs:

>>> stern hello-world + hello-world-pod › hello-world-container hello-world-pod hello-world-container /docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration hello-world-pod hello-world-container /docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/ hello-world-pod hello-world-container /docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh hello-world-pod hello-world-container 10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf hello-world-pod hello-world-container 10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf hello-world-pod hello-world-container /docker-entrypoint.sh: Sourcing /docker-entrypoint.d/15-local-resolvers.envsh hello-world-pod hello-world-container /docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh hello-world-pod hello-world-container /docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh hello-world-pod hello-world-container /docker-entrypoint.sh: Configuration complete; ready for start up hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: using the "epoll" event method hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: nginx/1.27.1 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: built by gcc 12.2.0 (Debian 12.2.0-14) hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: OS: Linux 6.6.49-1-lts hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker processes hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker process 29 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker process 30 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker process 31 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker process 32 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker process 33 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker process 34 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker process 35 hello-world-pod hello-world-container 2024/09/07 00:05:11 [notice] 1#1: start worker process 36

Link to this headingTilt

Launch with tilt:

tilt up --file Tiltfile.full-stack