In this tutorial, you'll start a local Kubernetes cluster with Minikube. You will then deploy Consul with the official Helm chart. After deploying Consul, you will learn how to access the agents. You will then deploy two services that use Consul to discover each other and communicate over TLS via Consul Connect service mesh.
Security Warning This tutorial is not for production use. By default, the chart will install an insecure configuration of Consul. Refer to the Kubernetes documentation to determine how you can secure Consul on Kubernetes in production. Additionally, it is highly recommended to use a properly secured Kubernetes cluster or make sure that you understand and enable the recommended security features.
»Prerequisites
First, you'll need to follow the directions for installing Minikube, including VirtualBox or a similar virtualization tool.
You'll also need to install kubectl and helm.
Install kubectl with Homebrew.
$ brew install kubernetes-cli
Install helm with Homebrew.
$ brew install kubernetes-helm
»Start Minikube
Start Minikube with the optional --memory flag specifying the equivalent of 4-8GB of memory, so your pods will have plenty of resources to use. Starting Minikube may take several minutes. It will download a 100-300MB of dependencies and container images.
$ minikube start --memory 4096
Next, use the minikube dashboard command to launch the local Kubernetes dashboard in a browser. Even if the previous step completed successfully, you may have to wait a minute or two for Minikube to be available. If you observe an error, try again after a few minutes.
$ minikube dashboard
Once it's available, you'll be able to access the dashboard in your web browser. You can review pods, nodes, and other resources.
»Install Consul with the official Helm chart
Tip: You can deploy a complete Consul datacenter using the official Helm chart. By default, the chart will install a three-server Consul datacenter on Kubernetes, with a Consul client on each Kubernetes node. You can review the official Helm chart values to learn more about the default settings.
»Download the demo code and Helm chart
First, add the HashiCorp Helm Chart repository:
$ helm repo add hashicorp https://helm.releases.hashicorp.com
"hashicorp" has been added to your repositories
»Create a custom values file
The chart comes with reasonable defaults, however, you will override a few values to help things go more smoothly with Minikube and enable useful features.
Create a custom values file called helm-consul-values.yaml with the following contents. Name the Consul datacenter and then enable the following:
- Consul UI via a
NodePort - secure communication between pods with
connectInject
Finally, you'll configure your deployment to only have one Consul server (suitable for local development).
# Choose an optional name for the datacenter
global:
datacenter: minidc
# Enable the Consul Web UI via a NodePort
ui:
service:
type: 'NodePort'
# Enable Connect for secure communication between nodes
connectInject:
enabled: true
# Enable CRD Controller
controller:
enabled: true
client:
enabled: true
# Use only one Consul server for local development
server:
replicas: 1
bootstrapExpect: 1
disruptionBudget:
enabled: true
maxUnavailable: 0
»Deploy Consul on Minikube
Now, run helm install, providing your custom values file, the hashicorp/consul chart, and a name for your Consul installation. It will print a list of all the resources that were created.
$ helm install -f helm-consul-values.yaml hashicorp hashicorp/consul
NAME: hashicorp
LAST DEPLOYED: Wed Nov 13 09:47:39 2019
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/DaemonSet
NAME AGE
hashicorp-consul 0s
==> v1/StatefulSet
hashicorp-consul-server 0s
==> v1/Pod(related)
NAME READY STATUS RESTARTS AGE
hashicorp-consul-fqzsz 0/1 ContainerCreating 0 0s
hashicorp-consul-connect-injector-webhook-deployment-5c7d4pvh5h 0/1 ContainerCreating 0 0s
==> v1/Service
hashicorp-consul-connect-injector-svc 0s
hashicorp-consul-dns 0s
hashicorp-consul-server 0s
hashicorp-consul-ui 0s
»Access the Consul UI
Verify Consul was deployed properly by accessing the Consul UI. Run minikube service list to list your services. Find the one with consul-ui in the name.
$ minikube service list
|-------------|----------------------------------------|-----------------------------|
| NAMESPACE | NAME | URL |
|-------------|----------------------------------------|-----------------------------|
| default | hashicorp-consul-server | No node port |
| default | hashicorp-consul-ui | http://192.168.99.100:31376 |
| default | kubernetes | No node port |
| kube-system | kube-dns | No node port |
| kube-system | kubernetes-dashboard | No node port |
| kube-system | tiller-deploy | No node port |
|-------------|----------------------------------------|-----------------------------|
Run minikube service with the consul-ui service name as the argument. It will open the service in your web browser.
$ minikube service hashicorp-consul-ui
You can now visit the Consul UI with a list of Consul's services, nodes, and other resources. Currently, you should only find the consul service listed.
»Access Consul with kubectl and the HTTP API
In addition to accessing Consul with the UI, you can manage Consul with the
HTTP API or by directly connecting to the pod with kubectl.
»Use Kubectl to access the server
To access the pod and data directory you can exec into the pod with kubectl to start a shell session.
First, get a list of all the Kubernetes pods.
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
hashicorp-consul-connect-injector-webhook-deployment-5c7d4pvh5h 1/1 Running 0 2m40s
hashicorp-consul-fqzsz 1/1 Running 0 2m40s
hashicorp-consul-server-0 1/1 Running 0 2m39s
Next, connect to the server using kubectl exec.
$ kubectl exec -it hashicorp-consul-server-0 -- /bin/sh
/ #
This will allow you to navigate the file system and run Consul CLI commands on the pod. For example you can verify the Consul version and member list.
$ consul version
Consul v1.6.1
Protocol 2 spoken by default, understands 2 to 3 (agent will automatically use protocol >2 when speaking to compatible agents)
$ consul members
Node Address Status Type Build Protocol DC Segment
hashicorp-consul-server-0 172.17.0.8:8301 alive server 1.6.1 2 kaitlin
minikube 172.17.0.2:8301 alive client 1.6.1 2 kaitlin
$ exit
»Consul HTTP API
You can use the Consul HTTP API by communicating with the local agent running on the Kubernetes node. Read the documentation to learn more about using the Consul HTTP API with Kubernetes.
»Deploy services with Kubernetes
Because you enabled the Connect injector in your values.yaml file, all the services using Consul service mesh will automatically be registered in the Consul catalog.
»Deploy two services
Now you can deploy your services as a two-tier application made of a backend data service that returns a number (the counting service) and a frontend dashboard that pulls from the counting service over HTTP and displays the number.
Create a pod definition and service account for the counting service named counting.yaml.
apiVersion: v1
kind: ServiceAccount
metadata:
name: counting
---
apiVersion: v1
kind: Pod
metadata:
name: counting
annotations:
'consul.hashicorp.com/connect-inject': 'true'
spec:
containers:
- name: counting
image: hashicorp/counting-service:0.0.2
ports:
- containerPort: 9001
name: http
serviceAccountName: counting
Next, create a pod definition and service account for the dashboard service and its load balancer named dashboard.yaml.
apiVersion: v1
kind: ServiceAccount
metadata:
name: dashboard
---
apiVersion: v1
kind: Pod
metadata:
name: dashboard
labels:
app: 'dashboard'
annotations:
'consul.hashicorp.com/connect-inject': 'true'
'consul.hashicorp.com/connect-service-upstreams': 'counting:9001'
spec:
containers:
- name: dashboard
image: hashicorp/dashboard-service:0.0.4
ports:
- containerPort: 9002
name: http
env:
- name: COUNTING_SERVICE_URL
value: 'http://localhost:9001'
serviceAccountName: dashboard
---
apiVersion: 'v1'
kind: 'Service'
metadata:
name: 'dashboard-service-load-balancer'
namespace: 'default'
labels:
app: 'dashboard'
spec:
ports:
- protocol: 'TCP'
port: 80
targetPort: 9002
selector:
app: 'dashboard'
type: 'LoadBalancer'
loadBalancerIP: ''
Use kubectl to deploy the counting service.
$ kubectl create -f counting.yaml
serviceaccount/counting created
pod/counting created
Use kubectl to deploy the dashboard service.
$ kubectl create -f dashboard.yaml
serviceaccount/dashboard created
pod/dashboard created
service/dashboard-service-load-balancer created
you observe
»Visit the dashboard
To visit the dashboard, forward the pod's port where the dashboard service is running to your local machine on the same port by providing the pod name (dashboard), which you specified in the service definition YAML file.
$ kubectl port-forward dashboard 9002:9002
Forwarding from 127.0.0.1:9002 -> 9002
Forwarding from [::1]:9002 -> 9002
Visit http://localhost:9002 in your web browser. It will display the dashboard service running in a Kubernetes pod, with a number retrieved from the counting service using Consul service discovery, and transmitted securely over the network with mutual TLS via an Envoy proxy.
»Secure service communication with intentions
Consul Connect service mesh secures service-to-service communication with authorization and encryption. Applications can use sidecar proxies to automatically establish mutual TLS connections for inbound and outbound network traffic without being aware of Consul at all.
Consul "intentions" provide you the ability to control which services are allowed to communicate. Next, you will use intentions to test the communication between the dashboard and counting services.
»Create an intention that denies communication
Connect to the Consul server using kubectl. Then use
the Consul CLI to create an intention to prevent the dashboard service from reaching its upstream counting service using the -deny flag.
$ kubectl exec hashicorp-consul-server-0 -- consul intention create -deny dashboard counting
Created: dashboard => counting (deny)
Verify the services are no longer allowed to communicate by returning to the dashboard UI. The service will display a message that the "Counting Service is Unreachable" and the count will display as "-1".
You can use consul intention create to manage "deny" and "allow" rules.
»Allow the application dashboard to communicate with the Counting service
Now, update the intention so that the services can communicate again.
$ kubectl exec hashicorp-consul-server-0 -- consul intention create dashboard counting
Created: dashboard => counting (allow)
These action does not require a reboot. Visit the application dashboard, and you'll notice that it's successfully communicating with the backend counting service again.
»Extend your knowledge
»Rolling updates to Consul
While running Consul you may want to make configuration and deployment updates.
You can use helm upgrade to increase the number of agents, enable additional
features, upgrade the Consul version, or change a your configuration. For example,
you could change the connectInject.default setting to true. If true, the injector
will inject the Connect sidecar into all pods by default. Otherwise, pods must
specify the injection annotation
to opt-in to Connect injection. If the default is set to true, pods can use the
same annotation to explicitly opt-out of injection.
You can practice using helm upgrade by updating your custom values file to enable
sidecar injection by default.
connectInject:
enabled: true
default: true
Initiate the upgrade
with the -f flag that passes in your new values file.
$ helm upgrade hashicorp -f helm-consul-values.yaml hashicorp/consul
Release "hashicorp" has been upgraded. Happy Helming!
...TRUNCATED...
Notice the basic Kubernetes services now appear in the Consul UI.
»Next steps
To learn more about Consul service mesh on Kubernetes, review the service mesh tutorials. Or, to learn how to deploy Consul on a Kubernetes cluster, review the production deployment tutorial.