.Manage Kubernete

.Manage Kubernete

# Contains :
# * attachment-rc.yml : How to attach a console to a process inside a pod
# * script.sh : Set of script for managing pods easily
# * minikube_on-mac.sh : Install minikube on macos

# Strace & Docker
# https://medium.com/@rothgar/how-to-debug-a-running-docker-container-from-a-separate-container-983f11740dc6

attachment-rc.yml

---
apiVersion: v1
kind: Pod
metadata:
  name: attachment
spec:
  containers:
  - name: count
    image: ubuntu
    stdin: true
    tty: true
    args: [bash, -c,
           'for ((i = 0; i < 20 ; i++)); do echo "$i: $(date)"; sleep 1; read; done']

# Config related to docker-for-mac only to check configmap & volume
    envFrom:
    - configMapRef:
        name: env-config
    volumeMounts:
    - name: data
      mountPath: /host_data/
  volumes:
  - name: data
    hostPath:
      path: /Users/.../kubernetes/data

# File credentials/env-config.yaml
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: env-config
  namespace: default
data:
  SAMPLE_ENV_VAR: SOME_VALUE

console.log

How to attach a console to a script running on a pod in kubernetes :

kubectl create -f attachment-rc.yml 
kubectl attach -ti attachment
kubectl delete -f attachment-rc.yml

This can be usefull for binding (debugging) purpose.

## check configmap & volume with docker-for-mac

# Create the credential
kubectl create -f ./credentials/env-config.yaml --context docker-for-desktop
# Launch the pod
kubectl create -f attachment-rc.yml --context=docker-for-desktop


# Verify that all is ok
kubectl get pods --context=docker-for-desktop
kubectl describe pod --context=docker-for-desktop


# Connect to the pod
kubectl exec -it --context docker-for-desktop attachment bash

# Verify that the credential is set :
> env | grep SAMPLE_ENV_VAR
> touch /host_data/toto # verify the file exist also on the host system

# IF NEEDED, delete the pod
kubectl delete -f attachment-rc.yml --context=docker-for-desktop --grace-period=0

minikube_on-mac.sh

brew install hyperkit
brew install docker-machine-driver-hyperkit
sudo chown root:wheel $(brew --prefix)/opt/docker-machine-driver-hyperkit/bin/docker-machine-driver-hyperkit
sudo chmod u+s $(brew --prefix)/opt/docker-machine-driver-hyperkit/bin/docker-machine-driver-hyperkit
#rm -rf ~/.minikube

minikube stop
minikube delete

echo "Removing hyperkit.pid file if present (https://github.com/kubernetes/minikube/issues/1926)...";

if [ -f ~/.minikube/machines/minikube/hyperkit.pid ]; then
  sudo rm ~/.minikube/machines/minikube/hyperkit.pid
  sudo rm -rf /var/db/dhcpd_leases
fi

echo "Configuring Minikube resource usage...";

machine_cpus="$(sysctl -n hw.ncpu)";
machine_memory="$(expr $(sysctl -n hw.memsize) / 1048576)"; # Bytes to megabytes conversion (x/2^20)
minikube_cpus="$(expr ${machine_cpus} / 2)";
minikube_memory="$(expr ${machine_memory} / 2)";

echo "Machine resources: ${machine_cpus} CPUs / ${machine_memory}MB Memory";
echo "Configure Minikube to use 50%: ${minikube_cpus} CPUs / ${minikube_memory}MB Memory";

echo "Running 'minikube start --vm-driver=hyperkit --cpus ${minikube_cpus} --memory ${minikube_memory}'..."

minikube start --vm-driver=hyperkit --cpus ${minikube_cpus} --memory ${minikube_memory} --v=10 --kubernetes-version v1.9.11 --mount --mount-string /Users:/Users --profile minihyperkit;
minikube addons enable ingress;

echo "Minikube started. Status:";
minikube status;

script.sh

# kube_console : Easy connect to your pods
# dependance : fzf, highlight
kube_console() {
  local window_cols=`tput cols`
  local window_lines=`tput lines`

  local context=${$(kubectl config view -o jsonpath='{range .contexts[*]}{@.name}{"\t"}(cluster={@.context.cluster}, namespace={@.context.namespace}, user={@.context.user}){"\n"}{end}' | sort | fzf --header="Select a context :" --exit-0 --select-1 --height 20% | awk '{print $1}'):-vagrant}

  local pods=$(kubectl get pods --context=$context -o=jsonpath='{.items[?(@.status.phase=="Running")].metadata.name}')
  local pod=$(echo $pods | tr ' ' '\n' | fzf --header='Select a pod :' --preview="kubectl describe pods {} --context=$context | highlight -O ansi --syntax=yaml"  | awk '{print $1}')

  local shell=$(kubectl exec $pod --context=$context  -i -t -- find /bin /usr/bin -regex '^\(/usr\)*/bin/\(fish\|ash\|sh\)$' | awk '{ print length($0) " " $0; }' | sort -r -n | cut -d ' ' -f 2- | head -1 | tr -d '\r')
  local shell_cmd="${@:-"\"$shell\""}"

  local CMD=(kubectl exec -ti $pod env COLUMNS=$window_cols LINES=$window_lines --context=$context -- /bin/sh -c "$shell_cmd")

  echo "Connection to $pod on $context with the following command : "
  echo $CMD
  $CMD
}

# kube_logs : Easy get logs from your pods
# dependance : fzf, stern, highlight
kube_logs() {
  local context=${$(kubectl config view -o jsonpath='{range .contexts[*]}{@.name}{"\t"}(cluster={@.context.cluster}, namespace={@.context.namespace}, user={@.context.user}){"\n"}{end}' | sort | fzf --header="Select a context :" --exit-0 --select-1 --height 20% | awk '{print $1}'):-vagrant}
  local application=$(kubectl get pods --context=$context -o=jsonpath='{.items[?(@.status.phase=="Running")].metadata.labels.app}' | tr ' ' '\n' | sort | uniq | fzf --header='Application label :' --preview="echo \"Pod(s) : \n\" &&kubectl get pods --context=$context  --selector app={} && echo \"\nHost(s) : \n\" && kubectl get ingress {} --context=$context -o jsonpath='{.spec.rules[*].host}'")

  local CMD
  CMD=(stern $application --context=$context --selector app=$application --timestamps --tail 50 --color always --exclude ".path.:.(/health/all|/api(?:/v\d+)?/public/build_version).")

  echo "Get aggregated logs for $application query on $context with the following command : "
  echo $CMD
  $CMD
}

# kube_attach : Attach to a pod that has stdin && tty enable
kube_attach() {
  local available_pods_data=$(kubectl get pods -o=jsonpath="{range .items[*]}[{.metadata.name}, {.metadata.namespace}, available_{.spec.containers[*]['.stdin','.tty']}_]{end}" | tr "][" '\n' | grep -i "available_true true_")
  local pod=$(echo "$available_pods_data" | tr "," " " | awk '{print $1}' | fzf --header='Select a pod :')

  local CMD
  CMD=(kubectl attach -ti $pod)

  echo "Attach to pod : $pod on default context & default namespace with the following command : "
  echo $CMD
  $CMD
}