Today I am going to show how to provision prepackaged k8s stacks with helm.
So what is Helm – here is literally what is’t page says – a tool for managing Kubernetes charts and Charts are packages of pre-configured Kubernetes resources. So imagine you want to provision some stack, ELK for example, although there are many ways to do it, here is one I did as an example for Jenkins logs although not on k8s but with just docker, but nevertheless, so instead of reinventing the wheel you just provision it using helm.
So let’s just do it instead of talking.
Go to download page and get the right version from https://github.com/kubernetes/helm
Then untar, move to right dir and run:
➜ tar -xzvf helm-v2.7.2-darwin-amd64.tar.gz ➜ mv darwin-amd64/helm /usr/local/bin ➜ helm The Kubernetes package manager To begin working with Helm, run the 'helm init' command: $ helm init .. ...
So let’s do what is asks:
helm init Creating /Users/kayanazimov/.helm Creating /Users/kayanazimov/.helm/repository Creating /Users/kayanazimov/.helm/repository/cache Creating /Users/kayanazimov/.helm/repository/local Creating /Users/kayanazimov/.helm/plugins Creating /Users/kayanazimov/.helm/starters Creating /Users/kayanazimov/.helm/cache/archive Creating /Users/kayanazimov/.helm/repository/repositories.yaml Adding stable repo with URL: https://kubernetes-charts.storage.googleapis.com Adding local repo with URL: http://127.0.0.1:8879/charts $HELM_HOME has been configured at /Users/kayanazimov/.helm. Tiller (the Helm server-side component) has been installed into your Kubernetes Cluster. Happy Helming!
We are now ready, let’s go with simple stack, mysql:
helm install --name mysqldb --set mysqlRootPassword=myrootpass,mysqlUser=myuser,mysqlPassword=mypass,mysqlDatabase=mydb stable/mysql NAME: mysqldb LAST DEPLOYED: Wed Dec 20 16:26:23 2017 NAMESPACE: default STATUS: DEPLOYED RESOURCES: ==> v1/Secret NAME TYPE DATA AGE mysqldb-mysql Opaque 2 1s ==> v1/PersistentVolumeClaim NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE mysqldb-mysql Bound pvc-852e3884-e5a2-11e7-8d68-0800277dff3a 8Gi RWO standard 1s ==> v1/Service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE mysqldb-mysql ClusterIP 10.0.0.154 <none> 3306/TCP 0s ==> v1beta1/Deployment NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE mysqldb-mysql 1 1 1 0 0s ==> v1/Pod(related) NAME READY STATUS RESTARTS AGE mysqldb-mysql-7848c56495-qnc8d 0/1 Pending 0 0s NOTES: MySQL can be accessed via port 3306 on the following DNS name from within your cluster: mysqldb-mysql.default.svc.cluster.local
As you can see it created Deployment, PersistentVolumeClaim, Secret, etc all resources needed and you can view secret for example by doing:
kubectl get secret --namespace default mysqldb-mysql -o jsonpath="{.data.mysql-root-password}" | base64 --decode; echo
myrootpass
Now let’s install and run a mysql client on ubuntu and try to connect to db:
kubectl run -i --tty ubuntu --image=ubuntu:16.04 --restart=Never -- bash -il apt-get update && apt-get install mysql-client -y .. ..... root@ubuntu:/# mysql -h mysqldb-mysql -p Enter password:
Once inside put your password ‘myrootpass’ and it is ready, let’s show databases:
Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 90 Server version: 5.7.14 MySQL Community Server (GPL) Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mydb | | mysql | | performance_schema | | sys | +--------------------+ 5 rows in set (0.00 sec)
As you can see, in couple steps you have fully ready mysql stack with persistence etc preconfigured with a single line of helm code. It is quite cool!