Deployment & Infrastructure
Connecting to Kubernetes

Connecting to Kubernetes

This section briefly shows how to do some basic connecting to Service and PODs in kubernetes cluster through kubectl or kubernetes OpenLens.
As stated you will obviously need access to our cluster. To login to specific cluster you can follow our Login guide.

How to connect to database

OpenLens

  1. Open OpenLens and on the left hand side panel navigate to Network -> Services.
  2. Find the Service that you want to connect to, usually something like anything-database or anything-database-service
  3. Click on right service and scroll down to find Connection section and under there should be a button Forward. Click it and choose your local free port
  4. Now your database should be accessible through localhost

Note: it is password free, but if you want to find password to db, go to secrets and find db secret for this db

kubectl

You can also port forward directly through kubectl command by running

kubectl port-forward service/anything-database-service 5432:5432

For more information checkout official port-forward (opens in a new tab) documentation.

How to see logs

OpenLens

You can follow this official video guide on extracting Logs https://www.youtube.com/watch?v=QIHqOd05TBA (opens in a new tab).

kubectl

You can get pod logs in you terminal with kubectl by running

kubectl get logs my-pod

For more information, check out interacting with running pods (opens in a new tab).

How to connect to app/pod terminal

OpenLens

  1. Open OpenLens and on the left hand side panel navigate to Workloads -> Pods
  2. Find the POD in question and click on it
  3. Click in right top corner find Pod Shell button (next to Pod Logs)

kubectl

If you prefer to attach to POD within your terminal, you can do so with kubectl

kubectl exec -i -t --namespace <namespace> <pod_name> --container <container> -- sh -c "clear; (bash || ash || sh)"

For example, to attach to pod with name "next-city-gallery-app-debug" in a namespace "bratislava-monorepo" and container "app", run the following

kubectl exec -i -t --namespace bratislava-monorepo next-city-gallery-app-debug --container app -- sh -c "clear; (bash || ash || sh)"

Tips & Tricks

If you are running reasonable *nix terminal you can automate most of these task from your terminal, here are just some examples

Attach to POD within your terminal without knowing full name

You can create a simple script, for example k8att.sh, that will search and attach to the right POD and it's container within your terminal. As this will search through available PODs you don't need to know full name to attach to as sometimes the PODs name can be long and in different namespaces.

#!/bin/bash
 
if [[ -z "$1" ]]
then
    echo "ERROR: You have to give us name of the pod to attach to"
    exit 1
fi
 
POD_RESP=$(kubectl get pods --all-namespaces | grep -E "$1")
POD_NAME=$(echo "$POD_RESP" | awk '{print $2}')
POD_NAMESPACE=$(echo "$POD_RESP" | awk '{print $1}')
 
POD_CONTAINERS=$(kubectl get pod --namespace "$POD_NAMESPACE" "$POD_NAME" -o jsonpath='{.spec.containers[*].name}')
IFS=' ' read -ra CONTAINERS <<< "$POD_CONTAINERS"
 
if [ "${#CONTAINERS[@]}" -gt 1 ]; then
    for i in "${!CONTAINERS[@]}"; do
        printf "%s\t%s\n" "$i" "${CONTAINERS[$i]}"
    done
    read -p "Choose container index (expecting int): " CONTAINER_IX
else
    CONTAINER_IX=0
fi
 
CONTAINER=${CONTAINERS[$CONTAINER_IX]}
echo -e "Attaching to pod \033[0;32m'$POD_NAME'\033[0m, container \033[0;32m'$CONTAINER'\033[0m in \033[0;34m'$POD_NAMESPACE'\033[0m namespace "
kubectl exec -i -t --namespace "$POD_NAMESPACE" "$POD_NAME" --container "$CONTAINER" -- sh -c "clear; (bash || ash || sh)"

Then you just chmod +x k8att.sh and you can use it to attach. Sticking with our previous attach example, now to attach to a pod "next-city-gallery-app-debug" you can just do

./k8att gallery-app-debug

If it has more containers to choose from, the script will prompt you to pick ID of the one that you want to attach to. Script use grep extended regex syntax, therefore you can also pass valid regex to it, e.g., gallery-[a-z]+-debug.

A very similar use are pod logs for which you can basically use the same script just adjust the last line to kubectl get logs.

You can add these scripts to your aliases in ~/.bashrc or ~/.bash_aliases

alias k8att='~/k8att.sh'
alias k8logs='~/k8logs.sh'

and just use it as any other command in your workflow.

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