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🌈 Update HAProxy example to use literal blue/green deployment
This commit is contained in:
Jérôme Petazzoni
@@ -1,18 +1,16 @@
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global
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daemon
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maxconn 256
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defaults
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mode tcp
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timeout connect 5000ms
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timeout client 50000ms
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timeout server 50000ms
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timeout connect 5s
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timeout client 50s
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timeout server 50s
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frontend the-frontend
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listen very-basic-load-balancer
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bind *:80
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default_backend the-backend
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backend the-backend
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server google.com-80 google.com:80 maxconn 32 check
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server ibm.fr-80 ibm.fr:80 maxconn 32 check
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server blue color.blue.svc:80
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server green color.green.svc:80
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# Note: the services above must exist,
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# otherwise HAproxy won't start.
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147
k8s/rainbow.yaml
Normal file
147
k8s/rainbow.yaml
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@@ -0,0 +1,147 @@
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---
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apiVersion: v1
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kind: Namespace
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metadata:
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name: blue
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labels:
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app: rainbow
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---
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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labels:
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app: rainbow
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color: blue
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name: color
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namespace: blue
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spec:
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selector:
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matchLabels:
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app: color
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color: blue
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template:
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metadata:
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labels:
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app: color
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color: blue
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spec:
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containers:
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- image: jpetazzo/color
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name: color
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---
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apiVersion: v1
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kind: Service
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metadata:
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labels:
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app: color
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color: blue
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name: color
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namespace: blue
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spec:
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ports:
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- name: http
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port: 80
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protocol: TCP
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targetPort: 80
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selector:
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app: color
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color: blue
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type: ClusterIP
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---
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apiVersion: v1
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kind: Namespace
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metadata:
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name: green
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labels:
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app: rainbow
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---
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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labels:
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app: rainbow
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color: green
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name: color
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namespace: green
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spec:
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selector:
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matchLabels:
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app: color
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color: green
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template:
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metadata:
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labels:
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app: color
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color: green
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spec:
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containers:
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- image: jpetazzo/color
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name: color
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---
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apiVersion: v1
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kind: Service
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metadata:
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labels:
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app: color
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color: green
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name: color
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namespace: green
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spec:
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ports:
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- name: http
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port: 80
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protocol: TCP
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targetPort: 80
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selector:
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app: color
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color: green
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type: ClusterIP
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---
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apiVersion: v1
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kind: Namespace
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metadata:
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name: red
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labels:
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app: rainbow
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---
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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labels:
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app: rainbow
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color: red
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name: color
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namespace: red
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spec:
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selector:
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matchLabels:
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app: color
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color: red
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template:
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metadata:
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labels:
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app: color
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color: red
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spec:
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containers:
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- image: jpetazzo/color
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name: color
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---
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apiVersion: v1
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kind: Service
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metadata:
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labels:
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app: color
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color: red
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name: color
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namespace: red
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spec:
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ports:
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- name: http
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port: 80
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protocol: TCP
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targetPort: 80
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selector:
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app: color
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color: red
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type: ClusterIP
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@@ -344,32 +344,94 @@ We'll cover them just after!*
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---
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## Passing a configuration file with a configmap
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## Example: HAProxy configuration
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- We will start a load balancer powered by HAProxy
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- We are going to deploy HAProxy, a popular load balancer
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- We will use the [official `haproxy` image](https://hub.docker.com/_/haproxy/)
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- It expects to find its configuration in a specific place:
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- It expects to find its configuration in `/usr/local/etc/haproxy/haproxy.cfg`
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`/usr/local/etc/haproxy/haproxy.cfg`
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- We will provide a simple HAproxy configuration, `k8s/haproxy.cfg`
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- We will create a ConfigMap holding the configuration file
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- It listens on port 80, and load balances connections between IBM and Google
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- Then we will mount that ConfigMap in a Pod running HAProxy
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---
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## Creating the configmap
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## Blue/green load balancing
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- In this example, we will deploy two versions of our app:
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- the "blue" version in the `blue` namespace
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- the "green" version in the `green` namespace
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- In both namespaces, we will have a Deployment and a Service
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(both named `color`)
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- We want to load balance traffic between both namespaces
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(we can't do that with a simple service selector: these don't cross namespaces)
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---
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## Deploying the app
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- We're going to use the image `jpetazzo/color`
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(it is a simple "HTTP echo" server showing which pod served the request)
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- We can create each Namespace, Deployment, and Service by hand, or...
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.exercise[
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- Go to the `k8s` directory in the repository:
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- We can deploy the app with a YAML manifest:
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```bash
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cd ~/container.training/k8s
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kubectl apply -f ~/container.training/k8s/rainbow.yaml
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```
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- Create a configmap named `haproxy` and holding the configuration file:
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]
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---
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## Testing the app
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- Reminder: Service `x` in Namespace `y` is available through:
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`x.y`, `x.y.svc`, `x.y.svc.cluster.local`
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- Since the `cluster.local` suffix can change, we'll use `x.y.svc`
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.exercise[
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- Check that the app is up and running:
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```bash
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kubectl create configmap haproxy --from-file=haproxy.cfg
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kubectl run --rm -it --restart=Never --image=nixery.dev/curl my-test-pod \
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curl color.blue.svc
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```
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]
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---
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## Creating the HAProxy configuration
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Here is the file that we will use, @@LINK[k8s/haproxy.cfg]:
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```
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@@INCLUDE[k8s/haproxy.cfg]
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```
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---
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## Creating the ConfigMap
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.exercise[
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- Create a ConfigMap named `haproxy` and holding the configuration file:
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```bash
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kubectl create configmap haproxy --from-file=~/container.training/k8s/haproxy.cfg
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```
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- Check what our configmap looks like:
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@@ -381,37 +443,21 @@ We'll cover them just after!*
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---
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## Using the configmap
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## Using the ConfigMap
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We are going to use the following pod definition:
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Here is @@LINK[k8s/haproxy.yaml], a Pod manifest using that ConfigMap:
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```yaml
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apiVersion: v1
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kind: Pod
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metadata:
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name: haproxy
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spec:
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volumes:
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- name: config
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configMap:
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name: haproxy
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containers:
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- name: haproxy
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image: haproxy
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volumeMounts:
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- name: config
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mountPath: /usr/local/etc/haproxy/
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@@INCLUDE[k8s/haproxy.yaml]
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```
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---
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## Using the configmap
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- The resource definition from the previous slide is in `k8s/haproxy.yaml`
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## Creating the Pod
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.exercise[
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- Create the HAProxy pod:
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- Create the HAProxy Pod:
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```bash
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kubectl apply -f ~/container.training/k8s/haproxy.yaml
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```
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@@ -430,27 +476,21 @@ spec:
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## Testing our load balancer
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- The load balancer will send:
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- If everything went well, when we should see a perfect round robin
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- half of the connections to Google
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- the other half to IBM
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(one request to `blue`, one request to `green`, one request to `blue`, etc.)
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.exercise[
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- Access the load balancer a few times:
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- Send a few requests:
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```bash
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for i in $(seq 10); do
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curl $IP
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curl $IP
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curl $IP
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done
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```
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]
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We should see connections served by Google, and others served by IBM.
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<br/>
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(Each server sends us a redirect page. Look at the URL that they send us to!)
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---
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## Exposing configmaps with the downward API
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@@ -490,27 +530,14 @@ We should see connections served by Google, and others served by IBM.
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We are going to use the following pod definition:
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```yaml
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apiVersion: v1
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kind: Pod
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metadata:
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name: registry
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spec:
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containers:
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- name: registry
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image: registry
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env:
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- name: REGISTRY_HTTP_ADDR
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valueFrom:
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configMapKeyRef:
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name: registry
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key: http.addr
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@@INCLUDE[k8s/registry.yaml]
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```
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---
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## Using the configmap
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- The resource definition from the previous slide is in `k8s/registry.yaml`
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- The resource definition from the previous slide is in @@LINK[k8s/registry.yaml]
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.exercise[
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