Installing multiple helm charts in one go [Approach 3 - using simple bash utility]

#helm #kubernetes #devops #linux

In this article, we will be talking about Approach 3 i.e. how to get multiple helm charts installed using a simple bash utility.

If you haven't read the previous article where I discussed other approaches, feel free to read it over.

Ref: Installing multiple helm charts in one go [Approach 1 - using parent/child charts]
Ref: Installing multiple helm charts in one go [Approach 2 - using helmfile]

Motive

Why I thought of a simple bash utility?

In some of the air-gapped environments it is sometimes a bit difficult to use the tools/utilities available because moving things inside an air-gapped environment is a challenge.
Some of the environments are so secure that one may need to follow a whole process of getting all the security clearances and approval before using a tool/utility, which altogether is a nightmare.
I chose bash, the reason being it is pretty common among engineers and it is easily understandable.
The source code can be found here: https://github.com/sunnybhambhani/helmister
You can copy it, and tweak it based on your requirements.

PS: I chose a name for this utility as well helmister or helm-minister but you can call it whatever you want 🙂

Prerequisites

A running Kubernetes cluster with proper permissions, here I have used minikube.
kubectl and helm installed on your machine to interact with the Kubernetes cluster.
- Ref: https://kubernetes.io/docs/tasks/tools/
- Ref: https://helm.sh/docs/intro/install/
A clone of helmister repository.
yq(required) and cowsay(optional) packages installed on your machine.

Helmister

This is a small bash utility that can help to install and uninstall multiple helm charts in one go. The idea is inspired by helmfile.
Its usage is quite simple, just run the utility followed by the option like install or uninstall i.e. ./helmister [install/uninstall].
Under the hood, it calls helm binary. Therefore it is kind of a wrapper around helm.
It consumes a config.yaml file which contains all the necessary details about the releases, and common parameters.
This supports both oci:// and https:// helm registries.
PS: In the future, I am planning to add some more options/functionalities to this.

Directory structure

.
├── config.yaml
├── helmister
├── logs
│   ├── archive
│   │   └── helmister_20240227_170201.tar.gz
│   └── helmister.log
├── README.md
└── values
    ├── argo-cd.yaml
    └── nginx-values.yaml

helmister, this is the script written in bash you can just cat and see what all things it contains.
config.yaml, this is the main configuration file or you can call the state file which contains the list of all releases you want to install in a cluster, plus it also contains some additional key:value pairs that are generic and common across all the releases. I first kept this configuration file in csv format, but later decided to convert it to yaml because it is more readable.
logs, this is a directory that holds the logs of this utility, it contains the information about the execution of the last iteration, plus any archived/past logs (if required for reference).
README.md, contains bit of a documentation about this utility, and what options are present.
values, this is the directory where all the values files are placed (it can be anywhere in your system but for simplicity, I have placed them in the same directory).
Now let's talk about config.yaml which is the main ingredient.

config.yaml

dry_run: false
create_namespace: true
wait: false
timeout: false # If true, defaults to 20 mins
charts:
  - release_name: nginx
    chart_name: nginx
    chart_repo: oci://registry-1.docker.io/bitnamicharts
    values_file: values/nginx-values.yaml
  - release_name: argocd
    chart_name: argo-cd
    chart_repo: https://argoproj.github.io/argo-helm
    values_file: values/argo-cd.yaml
    version: 6.4.0
    namespace: argo-cd

The initial key:value pairs are common across all the releases.
charts, is an array that contains a list of what all releases need to be installed in a Kubernetes cluster.
dry_run, it is a boolean [true or false], and if true, none of the Kubernetes resources will be created it will just do a dry_run.
create_namespace, it is a boolean [true or false], and if true it will automatically create a namespace for the release specified in the charts array.
wait, it is a boolean [true or false], and if true it acts similar to helm --wait wherein the shell will be kept occupied until all the Kubernetes resources are created.
timeout, it is a boolean [true or false], and if true it acts similar to helm --timeout=20m i.e. if all the resources are not created within 20 mins the execution will fail. By default, I have kept the timeout as 20 minutes which is more than enough.
charts, it is an array that contains details around individual releases. Except for version and namespace all the key:value pairs are mandatory.
- release_name, this is the name of the release.
- chart_name, this is the name of the chart that needs to be installed.
- chart_repo, this is the helm registry where the chart is located. It can be any oci:// or https:// registry.
- values_file, which contains the path of the values file for individual releases.
- version, this is the version of the chart that needs to be installed. This is optional and if not provided, It will consider the latest chart version.
- namespace, this is where the chart will be installed. This is optional as well and if not provided it will be installed in the default namespace.

Let's see this in action

I will use the same config.yaml which will install one helm release from an oci:// registry in default namespace (since I haven't specified any namespace for that release) and another one from https:// registry in argo-cd namespace. Note the version as well for nginx, there as well I haven't specified any version, it will pick the latest available one automatically.
This is my cluster's current status.

$ k get ns
NAME              STATUS   AGE
default           Active   28s
kube-node-lease   Active   28s
kube-public       Active   29s
kube-system       Active   29s

$ helm list -A
NAME    NAMESPACE       REVISION        UPDATED STATUS  CHART   APP VERSION

$ ./helmister install
[2024-07-23 15:02:47] [INFO] Using file: config.yaml
 ____________________________
< Helmister, Install charts! >
 ----------------------------
   \
    \
        .--.
       |o_o |
       |:_/ |
      //   \ \
     (|     | )
    /'\_   _/`\
    \___)=(___/

[2024-07-23 15:02:47] [INFO] Generic/common values based on config.yaml file
[2024-07-23 15:02:48] [INFO] Dry Run: false
[2024-07-23 15:02:48] [INFO] Create Namespace: true
[2024-07-23 15:02:48] [INFO] Wait: false
[2024-07-23 15:02:48] [INFO] Timeout: false
[2024-07-23 15:02:48] [INFO] ****************************
[2024-07-23 15:02:48] [INFO] Chart specific values based on config.yaml file
[2024-07-23 15:02:48] [INFO] Release Name: nginx
[2024-07-23 15:02:48] [INFO] Chart Name: nginx
[2024-07-23 15:02:48] [INFO] Chart Repo: oci://registry-1.docker.io/bitnamicharts
[2024-07-23 15:02:48] [INFO] Values File: values/nginx-values.yaml
[2024-07-23 15:02:48] [INFO] Version: null
[2024-07-23 15:02:48] [INFO] Namespace: null
[2024-07-23 15:02:48] [INFO] ****************************
[2024-07-23 15:02:48] [INFO] Installing nginx with release name nginx from oci://registry-1.docker.io/bitnamicharts with version null using values file: values/nginx-values.yaml in default namespace
...
...
OUTPUT TRIMMED

Actual stdout output can be found here.
Here you will see that it provides all the minute details of what exactly it is doing.
For example: Generic values
- Here I have marked create_namespace as true because I don't already have argo-cd namespace wherein I want to install argocd release.

[2024-07-23 15:02:47] [INFO] Generic/common values based on config.yaml file
[2024-07-23 15:02:48] [INFO] Dry Run: false
[2024-07-23 15:02:48] [INFO] Create Namespace: true
[2024-07-23 15:02:48] [INFO] Wait: false
[2024-07-23 15:02:48] [INFO] Timeout: false

Next, you will see, chart/release specific values of all the items in charts array one by one:

[2024-07-23 15:03:31] [INFO] Chart specific values based on config.yaml file
[2024-07-23 15:03:31] [INFO] Release Name: argocd
[2024-07-23 15:03:31] [INFO] Chart Name: argo-cd
[2024-07-23 15:03:31] [INFO] Chart Repo: https://argoproj.github.io/argo-helm
[2024-07-23 15:03:31] [INFO] Values File: values/argo-cd.yaml
[2024-07-23 15:03:31] [INFO] Version: 6.4.0
[2024-07-23 15:03:31] [INFO] Namespace: argo-cd

Here I have explicitly added an additional check that will check if the pods are up and healthy (this is just specific to pods it won't consider any other k8s objects).
It will continuously check for next 20mins and will check every 5 secs. If the pods are still in non-running state it will terminate the process.

[2024-07-23 15:03:47] [WARN] Pods for release argocd are not yet in Running state, checking again in 5 seconds

Once all the pods are in running state and it has deployed all the releases it will show a successful message.

[2024-07-23 15:05:20] [INFO] All actions completed successfully

Once this is done, if required you can see the logs as well from the logs directory. A sample can be found here.
And here is my cluster's current status now:

$ helm list -A
NAME    NAMESPACE       REVISION        UPDATED                                 STATUS          CHART           APP VERSION
argocd  argo-cd         1               2024-07-23 15:03:34.46715742 +0530 IST  deployed        argo-cd-6.4.0   v2.10.1
nginx   default         1               2024-07-23 15:02:53.590367521 +0530 IST deployed        nginx-18.1.5    1.27.0

$ k get ns
NAME              STATUS   AGE
argo-cd           Active   58m
default           Active   62m
kube-node-lease   Active   62m
kube-public       Active   62m
kube-system       Active   62m

$ k get pods -n argo-cd
NAME                                                READY   STATUS    RESTARTS   AGE
argocd-application-controller-0                     1/1     Running   0          58m
argocd-applicationset-controller-68cd75bc89-d4q8x   1/1     Running   0          58m
argocd-dex-server-84b5bbdcbf-c4qv2                  1/1     Running   0          58m
argocd-notifications-controller-7bc55c495d-xz6gt    1/1     Running   0          58m
argocd-redis-5d5cdcfd54-2rx26                       1/1     Running   0          58m
argocd-repo-server-756ff4cd7d-rpvh7                 1/1     Running   0          58m
argocd-server-7587d49b7b-9h47l                      1/1     Running   0          58m

$ k get pods -n default
NAME                     READY   STATUS    RESTARTS   AGE
nginx-569b6bc698-48qqt   1/1     Running   0          59m
nginx-569b6bc698-9qzpv   1/1     Running   0          59m
nginx-569b6bc698-wflrj   1/1     Running   0          59m