In this article I will install the free open-source edition of Traefik 2, version 2.3 being the latest at the time of writing, into a K3S (Kubernetes) cluster. Having installed Traefik 2 into my cluster, I will also take it for a quick test-drive.
What is Traefik?
Traefik will act as a gateway to the services deployed in a Kubernetes cluster, making it possible to access the selected services from outside of the Kubernetes cluster.
Some features provided by Traefik (not an exhaustive list):
- Reverse proxy.
- Load balancing.
- Adding basic authentication to servers/services.
- Authentication delegation.
- Automatic service discovery.
- IP address whitelisting.
- Circuit breaking.
- Rate limiting.
- Access logging.
- Compress responses.
- Can publish metrics.
- Retry request in case of errors.
- Supports distributed tracing using OpenTracing.
In the case where Traefik is deployed to a Kubernetes cluster, it will act as an ingress controller.
Please refer to the Traefik documentation for further details!
The prerequisites for my K3S cluster are:
Manages the virtual machines in which K3S will be installed.
Instructions on how to install Multipass can be found here.
The Kubernetes command-line cluster management tool.
Instructions on how to install kubectl can be found here.
kubectl will be configured after having installed K3S.
- Two virtual machines in which to install K3S.
Please refer to my earlier article on installing K3S in Multipass VMs for instructions on how to create the virtual machines. Do NOT install K3S in the virtual machines!
The installation process is, for most parts, identical to what I described in my earlier article. The difference is that this time I will exclude the default version of Traefik, which at the time of writing is Traefik 1.
Install K3S on Master Node
First I am going to install K3S on the master node.
- Open a terminal window.
- Open a shell on the k3s-master VM:
multipass shell k3s-master
- Install the latest version of K3S for a master node, excluding the default version of Traefik:
curl -sfL https://get.k3s.io | sh -s - --disable=traefik
Output similar to the following should appear in the console:
[INFO] Finding release for channel stable [INFO] Using v1.18.9+k3s1 as release [INFO] Downloading hash https://github.com/rancher/k3s/releases/download/v1.18.9+k3s1/sha256sum-amd64.txt [INFO] Downloading binary https://github.com/rancher/k3s/releases/download/v1.18.9+k3s1/k3s [INFO] Verifying binary download [INFO] Installing k3s to /usr/local/bin/k3s [INFO] Creating /usr/local/bin/kubectl symlink to k3s [INFO] Creating /usr/local/bin/crictl symlink to k3s [INFO] Creating /usr/local/bin/ctr symlink to k3s [INFO] Creating killall script /usr/local/bin/k3s-killall.sh [INFO] Creating uninstall script /usr/local/bin/k3s-uninstall.sh [INFO] env: Creating environment file /etc/systemd/system/k3s.service.env [INFO] systemd: Creating service file /etc/systemd/system/k3s.service [INFO] systemd: Enabling k3s unit Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service → /etc/systemd/system/k3s.service. [INFO] systemd: Starting k3s
- Check the configuration of K3S installed on the master node:
Verifying binaries in /var/lib/rancher/k3s/data/688c8ca42a6cd0c042322efea271d6f3849d3de17c850739b0da2461f6c69ee8/bin: - sha256sum: good - links: good System: - /sbin iptables v1.6.1: older than v1.8 - swap: disabled - routes: ok Limits: - /proc/sys/kernel/keys/root_maxkeys: 1000000 modprobe: FATAL: Module configs not found in directory /lib/modules/4.15.0-118-generic info: reading kernel config from /boot/config-4.15.0-118-generic ... Generally Necessary: - cgroup hierarchy: properly mounted [/sys/fs/cgroup] - /sbin/apparmor_parser apparmor: enabled and tools installed - CONFIG_NAMESPACES: enabled - CONFIG_NET_NS: enabled - CONFIG_PID_NS: enabled - CONFIG_IPC_NS: enabled - CONFIG_UTS_NS: enabled - CONFIG_CGROUPS: enabled - CONFIG_CGROUP_CPUACCT: enabled - CONFIG_CGROUP_DEVICE: enabled - CONFIG_CGROUP_FREEZER: enabled - CONFIG_CGROUP_SCHED: enabled - CONFIG_CPUSETS: enabled - CONFIG_MEMCG: enabled - CONFIG_KEYS: enabled - CONFIG_VETH: enabled (as module) - CONFIG_BRIDGE: enabled (as module) - CONFIG_BRIDGE_NETFILTER: enabled (as module) - CONFIG_NF_NAT_IPV4: enabled (as module) - CONFIG_IP_NF_FILTER: enabled (as module) - CONFIG_IP_NF_TARGET_MASQUERADE: enabled (as module) - CONFIG_NETFILTER_XT_MATCH_ADDRTYPE: enabled (as module) - CONFIG_NETFILTER_XT_MATCH_CONNTRACK: enabled (as module) - CONFIG_NETFILTER_XT_MATCH_IPVS: enabled (as module) - CONFIG_IP_NF_NAT: enabled (as module) - CONFIG_NF_NAT: enabled (as module) - CONFIG_NF_NAT_NEEDED: enabled - CONFIG_POSIX_MQUEUE: enabled Optional Features: - CONFIG_USER_NS: enabled - CONFIG_SECCOMP: enabled - CONFIG_CGROUP_PIDS: enabled - CONFIG_BLK_CGROUP: enabled - CONFIG_BLK_DEV_THROTTLING: enabled - CONFIG_CGROUP_PERF: enabled - CONFIG_CGROUP_HUGETLB: enabled - CONFIG_NET_CLS_CGROUP: enabled (as module) - CONFIG_CGROUP_NET_PRIO: enabled - CONFIG_CFS_BANDWIDTH: enabled - CONFIG_FAIR_GROUP_SCHED: enabled - CONFIG_RT_GROUP_SCHED: missing - CONFIG_IP_NF_TARGET_REDIRECT: enabled (as module) - CONFIG_IP_SET: enabled (as module) - CONFIG_IP_VS: enabled (as module) - CONFIG_IP_VS_NFCT: enabled - CONFIG_IP_VS_PROTO_TCP: enabled - CONFIG_IP_VS_PROTO_UDP: enabled - CONFIG_IP_VS_RR: enabled (as module) - CONFIG_EXT4_FS: enabled - CONFIG_EXT4_FS_POSIX_ACL: enabled - CONFIG_EXT4_FS_SECURITY: enabled - Network Drivers: - "overlay": - CONFIG_VXLAN: enabled (as module) Optional (for encrypted networks): - CONFIG_CRYPTO: enabled - CONFIG_CRYPTO_AEAD: enabled - CONFIG_CRYPTO_GCM: enabled - CONFIG_CRYPTO_SEQIV: enabled - CONFIG_CRYPTO_GHASH: enabled - CONFIG_XFRM: enabled - CONFIG_XFRM_USER: enabled (as module) - CONFIG_XFRM_ALGO: enabled (as module) - CONFIG_INET_ESP: enabled (as module) - CONFIG_INET_XFRM_MODE_TRANSPORT: enabled (as module) - Storage Drivers: - "overlay": - CONFIG_OVERLAY_FS: enabled (as module) STATUS: pass
Notice the last line saying “STATUS: pass”, which means that the K3S master node installation has been verified and found satisfactory.
- Retrieve the master node token:
sudo cat /var/lib/rancher/k3s/server/node-token
This token will be different for each installation. It is needed when installing the agent node(s). In my case it looks like this:
- Exit the k3s-master VM shell:
- Find the IP address of the master node, which will be needed when installing K3S on the agent node:
Name State IPv4 Image k3s-master Running 192.168.64.7 Ubuntu 18.04 LTS
Install K3S on Agent Node
Having installed K3S on the master node and obtained the master node token, I can now install K3S on the agent node:
- Open a terminal window if needed.
- Open a shell on the k3s-agent VM:
multipass shell k3s-agent01
- Install K3S for an agent node.
Remember to replace the master node IP address and master node token with your values!
curl -sfL https://get.k3s.io | K3S_URL="https://192.168.64.7:6443" K3S_TOKEN="K10288e77934e06dda1e7523114282478fdc1798545f04235a86b97c71a0bca41f4::server:baecfccac88699f5a12e228e72a69cf2" sh -
Console output from K3S agent installation should look similar to this:
[INFO] Finding release for channel stable [INFO] Using v1.18.9+k3s1 as release [INFO] Downloading hash https://github.com/rancher/k3s/releases/download/v1.18.9+k3s1/sha256sum-amd64.txt [INFO] Downloading binary https://github.com/rancher/k3s/releases/download/v1.18.9+k3s1/k3s [INFO] Verifying binary download [INFO] Installing k3s to /usr/local/bin/k3s [INFO] Creating /usr/local/bin/kubectl symlink to k3s [INFO] Creating /usr/local/bin/crictl symlink to k3s [INFO] Creating /usr/local/bin/ctr symlink to k3s [INFO] Creating killall script /usr/local/bin/k3s-killall.sh [INFO] Creating uninstall script /usr/local/bin/k3s-agent-uninstall.sh [INFO] env: Creating environment file /etc/systemd/system/k3s-agent.service.env [INFO] systemd: Creating service file /etc/systemd/system/k3s-agent.service [INFO] systemd: Enabling k3s-agent unit Created symlink /etc/systemd/system/multi-user.target.wants/k3s-agent.service → /etc/systemd/system/k3s-agent.service. [INFO] systemd: Starting k3s-agent
- Check the configuration of K3S installed on the agent node.
The output to the console should be almost identical to the corresponding output on the master node earlier. In my case, there is I difference (highlighted) in the System section:
System: - /sbin iptables v1.6.1: older than v1.8 - swap: disabled - routes: default CIDRs 10.42.0.0/16 or 10.43.0.0/16 already routed’
However, at the end of the output, the status is still pass.
- Exit the k3s-agent01 VM shell:
Configuration of kubectl that I have installed in the VM host to manage my K3S cluster is described in my previous article.
Installing Helm 3
- Execute the following in a terminal window:
curl https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3 | bash
If already installed, the above script will update Helm 3 if there is a newer version available. If the latest version of Helm 3 is already installed, the script will inform you and exit.
Finally it is time to install Traefik 2 in the K3S cluster!
- Add Traefik 2’s Helm chart repository:
helm repo add traefik https://helm.traefik.io/traefik
- Update local information of available charts from chart repositories:
helm repo add traefik https://helm.traefik.io/traefik
- Create a Kubernetes namespace in which to install Traefik 2:
kubectl create ns traefik-v2
- Download the Traefik 2 default Helm values file from https://github.com/traefik/traefik-helm-chart/blob/master/traefik/values.yaml
This step can be skipped if you do not want to make any modifications to the Traefik Helm chart values.
- Modify the content of the values file as you find suitable.
I am going to use the default values file, without any modifications. I could have skipped the values file altogether but wanted to include the option to customize the Traefik installation.
This step can be skipped if you do not want to make any modifications to the Traefik Helm chart values.
- Install Traefik 2:
helm install --namespace=traefik-v2 --values=./values.yaml traefik traefik/traefik
If you haven’t made any modifications to the Traefik Helm chart values, the following command should be used instead:
helm install --namespace=traefik-v2 traefik traefik/traefik
Example output from the Traefik installation:
NAME: traefik LAST DEPLOYED: Thu Oct 22 21:11:19 2020 NAMESPACE: traefik-v2 STATUS: deployed REVISION: 1 TEST SUITE: None
- Verify that the Traefik pods have been successfully started:
kubectl get pods -n=traefik-v2 -o wide
Example output showing the Traefik pods:
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES svclb-traefik-895t4 2/2 Running 0 61s 10.42.0.8 k3s-master <none> <none> svclb-traefik-ztjj6 2/2 Running 0 61s 10.42.1.3 k3s-agent01 <none> <none> traefik-7fb947cdf7-sjjf8 1/1 Running 0 61s 10.42.1.2 k3s-agent01 <none> <none>
All the pods should have the status running.
View Traefik Dashboard
The Traefik dashboard lets you view the current state of Traefik in your cluster.
- List the Traefik pod:
kubectl get pods -n traefik-v2 --selector "app.kubernetes.io/name=traefik" --output name
- Forward requests on localhost port 9000 to the Traefik pod from the previous step.
Note that you will have to replace the name of the Traefik pod with the name obtained in the previous step!
kubectl port-forward -n traefik-v2 pod/traefik-7fb947cdf7-sjjf8 9000:9000
- In a browser, navigate to http://127.0.0.1:9000/dashboard/
The dashboard should look like this:
The deployment used in the example, stored in a file with the name “01_example-deployment.yaml”, looks like this:
apiVersion: apps/v1 kind: Deployment metadata: namespace: default name: whoami labels: app: whoami spec: replicas: 2 selector: matchLabels: app: whoami template: metadata: labels: app: whoami spec: containers: - name: whoami image: traefik/whoami ports: - name: web containerPort: 80
- Deployment is a standard Kubernetes resource (apiVersion: apps/v1).
- The deployment uses the traefik/whoami image.
This is a small webserver that, when receiving a HTTP request, prints out information about the request etc.
- The server will be listening on port 80, named “web”, in the pod(s) it will be running.
- All pods created from this deployment will have the lablel app=whoami as specified by spec.template.metadata.labels.
The service defines a set of pods that are to process requests as a single service. The service definition used in the example is stored in a file with the name “02_example-service.yaml” and looks like this:
apiVersion: v1 kind: Service metadata: name: whoami spec: ports: - port: 80 targetPort: web selector: app: whoami
- Service is also a standard Kubernetes resource (apiVersion: v1).
- The service will be made available on port 80, as specified by spec.ports.port.
- Requests to the service will be forwarded to the port with the name “web” in the pod(s) backing the service, as specified by spec.ports.targetPort.
- All pods with the label app=whoami will be part of the service.
The final part of the example is the ingress route, which is listed below. It is stored in a file with the name “03_example-plainhttp-ingressroute.yaml”.
apiVersion: traefik.containo.us/v1alpha1 kind: IngressRoute metadata: name: simpleingressroute namespace: default spec: entryPoints: - web routes: - match: PathPrefix(`/whoami`) kind: Rule services: - name: whoami port: 80
- The IngressRoute is a Traefik resource (apiVersion: traefik.containo.us/v1alpha1).
- The IngressRoute will have the name “simpleingressroute”.
- The IngressRoute will be created in the “default” namespace.
- The entry point on which this ingress route will accept connections is the web entry point.
This is the plain HTTP entry point. The name of the HTTPS entry point is “websecure”.
- There is a route definition.
The route will match all requests with the path prefix “/whoami” and route them to a service with the name “whoami” on port 80. As if by coincidence, this perfectly matches the service defined above!
Applying the Example Configuration
With the three files in place, we are now ready to apply the configuration using the following commands:
kubectl apply -f 01_example-deployment.yaml kubectl apply -f 02_example-service.yaml kubectl apply -f 03_example-plainhttp-ingressroute.yaml
Examine the pods created by the deployment:
kubectl get pods
The result should be similar to this:
NAME READY STATUS RESTARTS AGE whoami-5db58df676-gfrsn 1/1 Running 1 3s whoami-5db58df676-sgm6t 1/1 Running 1 3s
Examine the service created:
kubect get service whoami
The result should look like this:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE whoami ClusterIP 10.43.185.44 <none> 80/TCP 4m
Note that the service has no external IP.
Examine the ingress route:
kubectl get ingressroute
The result should look like:
NAME AGE simpleingressroute 3s
Accessing the Service
In order to be able to access the whoami service, we first need to find the port and IP address of the Traefik service:
kubectl get svc -n traefik-v2
The output should look like this:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE traefik LoadBalancer 10.43.4.135 192.168.64.8 80:30074/TCP,443:30261/TCP 7d
The external IP address of the Traefik load balancer is, in my case, 192.168.64.8. Since we were using the web entry point in the ingress route, we want to look at the port that is mapped to port 80, which in my case is port 30074. Recall also that in the ingress route, we defined matching against the path prefix “/whoami”.
Thus the URL at which I can access the whoami service will be:
When entering the above URL in a browser, the response is:
Hostname: whoami-5db58df676-sgm6t IP: 127.0.0.1 IP: ::1 IP: 10.42.2.6 IP: fe80::9403:3ff:fee0:3627 RemoteAddr: 10.42.1.11:53602 GET /whoami HTTP/1.1 Host: 192.168.64.8:30074 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:83.0) Gecko/20100101 Firefox/83.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 Accept-Encoding: gzip, deflate Accept-Language: en-US,en;q=0.5 Dnt: 1 Sec-Gpc: 1 Upgrade-Insecure-Requests: 1 X-Forwarded-For: 10.42.1.1 X-Forwarded-Host: 192.168.64.8:30074 X-Forwarded-Port: 30074 X-Forwarded-Proto: http X-Forwarded-Server: traefik-7fb947cdf7-sjjf8 X-Real-Ip: 10.42.1.1
We have succeeded exposing the whoami service to the world outside of the Kubernetes cluster using Traefik v2.