https://github.com/francomelandri/helm-blue-green
Spike on Blue/Green deploy using Helm
https://github.com/francomelandri/helm-blue-green
Last synced: 8 months ago
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Spike on Blue/Green deploy using Helm
- Host: GitHub
- URL: https://github.com/francomelandri/helm-blue-green
- Owner: FrancoMelandri
- License: gpl-3.0
- Created: 2020-03-05T12:30:46.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2020-03-14T10:07:58.000Z (over 5 years ago)
- Last Synced: 2025-02-05T04:51:17.749Z (10 months ago)
- Language: C#
- Size: 94.7 KB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Blue Green with Helm
This spike is about implementing a **Blue/Green** deployment strategy using helm package manager. To be honest Helm wasn't born thinking about B/G but with some trick we are able to do it.
This is an implementation related to the article here https://medium.com/@saraswatpuneet/blue-green-deployments-using-helm-charts-93ec479c0282
## What we need...
- docker desktop, minikube or a real K8s cluster
- Helm version 3 or above
- Nginx as ingress
- A simple service (build using dot net core)
## Installing NGINX
In the nginx folder you can find two yaml file coming directly from nginx we site. The only difference is about the namespace. We are going to use **default** instead of **ingress-nginx**.
```bash
> kubectl apply -f nginx/mandatory.yaml
> kubectl apply -f nginx/cloud-generic.yaml
```
## my-service
In order to test the blue/green deployment we are going to use a little service developed using dotnet core. This service expose a resource ```/weatherforecast/slot``` returning a simple string like this
```c#
[HttpGet("slot")]
public string Slot()
=> $"{_serviceDescription.Slot} - {_serviceDescription.Version}";
```
## Topology
Looking at the yaml files in the template folder
```
.
├── Chart.yaml
├── deploy.yaml
├── templates
│ ├── blue
│ │ ├── config.yaml
│ │ └── deployment.yaml
│ ├── green
│ │ ├── config.yaml
│ │ └── deployment.yaml
│ ├── ingress.yaml
│ └── service.yaml
└── values.yaml
```
we get the following topology of the system
where the service use the selector **slot:blue|green** to point the the right deployment.
## Release 0.1.0
deploy.yaml
```yaml
blue:
version: "0.1.0"
green:
version: "0.1.0"
productionSlot: green
```
command
```bash
helm upgrade my-service helm/ --debug --install -f helm/deploy.yaml
```
result
```bash
> kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
ingress-nginx LoadBalancer 10.97.201.105 localhost 80:31940/TCP,443:30232/TCP 42h
kubernetes ClusterIP 10.96.0.1 443/TCP 2d3h
my-service ClusterIP 10.102.1.193 80/TCP 38m
> kubectl get configmap
NAME DATA AGE
ingress-controller-leader-nginx 0 42h
my-service-blue 1 39m
my-service-green 1 39m
nginx-configuration 0 42h
tcp-services 0 42h
udp-services 0 42h
> kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
my-service-blue 1/1 1 1 40m
my-service-green 1/1 1 1 40m
nginx-ingress-controller 1/1 1 1 42h
> kubectl get pods
NAME READY STATUS RESTARTS AGE
my-service-blue-598ffcc8d5-qwbbn 1/1 Running 0 2m37s
my-service-green-7fb46c446d-mx8gs 1/1 Running 0 40m
nginx-ingress-controller-7f74f657bd-gfxcv 1/1 Running 0 42h
❯ curl http://localhost/weatherforecast/slot -v
* Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost.prd (127.0.0.1) port 80 (#0)
> GET /weatherforecast/slot HTTP/1.1
> Host: localhost.prd
> User-Agent: curl/7.58.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Server: nginx/1.17.8
< Date: Thu, 05 Mar 2020 12:04:25 GMT
< Content-Type: text/plain; charset=utf-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Vary: Accept-Encoding
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Credentials: true
< Access-Control-Allow-Methods: GET, PUT, POST, DELETE, PATCH, OPTIONS
< Access-Control-Allow-Headers: DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Authorization
<
* Connection #0 to host localhost.prd left intact
green - 0.1.0#
```
## Deploy 0.2.0 on stage
deploy.yaml
```yaml
blue:
version: "0.2.0"
green:
version: "0.1.0"
productionSlot: green
```
command
```bash
> helm upgrade my-service helm/ --debug --install -f helm/deploy.yaml
```
result
```bash
❯ curl http://localhost/weatherforecast/slot -v
* Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost.stg (127.0.0.1) port 80 (#0)
> GET /weatherforecast/slot HTTP/1.1
> Host: localhost.stg
> User-Agent: curl/7.58.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Server: nginx/1.17.8
< Date: Thu, 05 Mar 2020 12:08:58 GMT
< Content-Type: text/plain; charset=utf-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Vary: Accept-Encoding
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Credentials: true
< Access-Control-Allow-Methods: GET, PUT, POST, DELETE, PATCH, OPTIONS
< Access-Control-Allow-Headers: DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Authorization
<
* Connection #0 to host localhost.stg left intact
green - 0.1.0#
```
## Switching prod to blue
deploy.yaml
```yaml
blue:
version: "0.2.0"
green:
version: "0.1.0"
productionSlot: blue
```
command
```bash
> helm upgrade my-service helm/ --debug --install -f helm/deploy.yaml
```
result
```bash
❯ curl http://localhost/weatherforecast/slot -v
* Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost.stg (127.0.0.1) port 80 (#0)
> GET /weatherforecast/slot HTTP/1.1
> Host: localhost.stg
> User-Agent: curl/7.58.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Server: nginx/1.17.8
< Date: Thu, 05 Mar 2020 12:08:58 GMT
< Content-Type: text/plain; charset=utf-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Vary: Accept-Encoding
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Credentials: true
< Access-Control-Allow-Methods: GET, PUT, POST, DELETE, PATCH, OPTIONS
< Access-Control-Allow-Headers: DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Authorization
<
* Connection #0 to host localhost.stg left intact
blue - 0.2.0#
```
Now the command to switch immediately from green to blue is:
```bash
> kubectl patch svc my-service -p '{"spec":{"selector":{"slot": "blue"}}}'
```
That allow you to change the selector of the service in order to route the traffic to the blue deployment set instead of the green one.