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Eduardo Issao Ito
Eduardo Issao Ito

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Resumo Kubernetes

#kubernetes #k8s #kubectl #aks

Configurar cluster

Configurar kubectl para acessar um Azure AKS

az aks get-credentials -g ${GROUP} -n ${CLUSTER}
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Ver configurações do kubectl

kubectl config view
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Adicionando um novo cluster ao kubectl

# Add a user/principal that will be used when connecting to the cluster kubectl config set-credentials kubeuser/foo.com --username=kubeuser --password=kubepassword # Point to a cluster kubectl config set-cluster foo.com --insecure-skip-tls-verify=true --server=https://foo.com # This context points to the cluster with a specific user kubectl config set-context default/foo.com/kubeuser --user=kubeuser/foo.com --namespace=default --cluster=foo.com # Use this specific context kubectl config use-context default/foo.com/kubeuser
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Trocando de cluster

# Mostrando os clusters configurados no ~/.kube kubectl config get-contexts # Mostrando o contexto atual kubectl config current-context # Trocando de contexto kubectl config use-context CONTEXT_NAME
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Namespaces

Criando um namespace

kubectl create namespace ${NAMESPACE}
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Listando os namespaces existentes:

kubectl get namespaces
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Trocando o namespace corrente

kubectl config set-context --current --namespace=${NAMESPACE}
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Pods

Procurar (por label)

kubectl get pods -l app=MY-APP POD_NAME=$(kubectl get pods -o=jsonpath='{.items[?(@.metadata.labels.app=="MY-APP")].metadata.name}')
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Describe (ver eventos)

kubectl describe pod $POD_NAME
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Logs (da aplicação)

kubectl logs $POD_NAME
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Mostrar os nodes de execução dos pods

kubectl get pods -o=wide # Filtrar pelo nome do node kubectl get pods --field-selector spec.nodeName=$NODE_NAME
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Terminal

Abrir terminal num pod

kubectl exec --stdin --tty $POD_NAME -- /bin/bash
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Se estiver usando um terminal Git-bash ou MinGW, colocar a variável MSYS_NO_PATHCONV:

MSYS_NO_PATHCONV=1 kubectl exec --stdin --tty $POD_NAME -- /bin/bash

Service

Acessando um serviço

kubectl get svc ${SERVICE_NAME} EXTERNAL_IP=$(kubectl get svc ${SERVICE_NAME} -o=jsonpath='{.status.loadBalancer.ingress[0].ip}') curl http: ${EXTERNAL_IP}/api/v1/hello
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Expondo um endereço:

kubectl port-forward service/${SERVICE_NAME} 9200:9200
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Logs 

kubectl logs -p $POD --all-containers --previous=false
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Restart pods

Sem downtime:

kubectl rollout restart deployment <deployment_name>
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Parando todos pods e depois reiniciando todos:

kubectl scale deployment <deployment name> - replicas=0 kubectl scale deployment <deployment name> - replicas=1
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Alterando uma variável associada ao pod:

kubectl set env deployment <deployment name> LAST_START_DATE="$(date)"
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Selecionando um pod específico:

kubectl delete pod <pod_name>
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Selecionando todos pods com label:

kubectl delete pod -l "app:myapp"
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Performance

Mostra consumo de CPU e MEMORY de pods

kubectl top pod kubectl top pod POD_ID
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