Kubernetes with external Ingress Controller

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In this post I will show you how to nstall HAProxy Igress Controller on a separate VM instad of running it in the Kubernetes cluster as a pod. For this I will use cilium external-workload option.

At the company I working wor we head to create a kubernetes cluster with the DMZ network integration, but I didn’t want to place the kubernetes cluster to the DMZ network. So I started to find a way to place only the Ingress Controller to a separate node and place only that to the DMZ. I found thet ther is an option with the HAProxy Igress Controller called external mode wher you can run the Ingress Controller not in a pod in the cluster but on a separate node.

Prerequisites

  • recent enough kernel (>= 4.19.57)
  • Docker 20.10 or newer
  • External workloads VM must have IP connectivity with the nodes on vxlan port 8472/udp
  • External workloads VM must have IP connectivity with loadbalancer IP and port
  • External workloads VM must have IP connectivity for kubernetes api
  • All external workloads must have a unique IP address assigned them
  • This guide assumes your external workload manages domain name resolution service by a stand-alone /etc/resolv.conf, or via systemd (e.g., Ubuntu, Debian).

Ciliium config

helm upgrade cilium cilium/cilium -f cilium-helm-values.yaml -n kube-system

cilium status

cilium clustermesh enable --service-type LoadBalancer --enable-external-workloads
cilium clustermesh vm create f101 -n ingress-system --ipv4-alloc-cidr 10.244.20.0/30
cilium clustermesh vm status
cilium clustermesh vm install install-external-workload.sh

scp install-external-workload.sh f101:

The vm object name must be the hostname of the external workload, as returned by the hostname command run in the external workload. In this example this is f101. For now you must also allocate a small IP CIDR that must be unique to each workload. In this example this is 10.244.20.0/30.

Install Cilium external workload

On the External Ingress COntroller’s VM we vill install cilium agent with the script:

./install-external-workload.sh
sudo cilium-dbg status

KVStore:                 Ok         etcd: 1/1 connected, leases=1, lock leases=1, has-quorum=true: https://clustermesh-apiserver.cilium.io:2379 - 3.5.12 (Leader)
Kubernetes:              Disabled
Host firewall:           Disabled
SRv6:                    Disabled
CNI Chaining:            none
Cilium:                  Ok   1.15.3 (v1.15.3-22dfbc58)
NodeMonitor:             Disabled
Cilium health daemon:    Ok
IPAM:                    IPv4: 1/2 allocated from 10.244.20.0/30, IPv6: 1/4294967294 allocated from f00d::a0f:0:0:0/96
IPv4 BIG TCP:            Disabled
IPv6 BIG TCP:            Disabled
BandwidthManager:        Disabled
Host Routing:            Legacy
Masquerading:            IPTables [IPv4: Enabled, IPv6: Enabled]
Controller Status:       14/14 healthy
Proxy Status:            OK, ip 10.244.20.2, 0 redirects active on ports 10000-20000, Envoy: embedded
Global Identity Range:   min 256, max 65535
Hubble:                  Disabled
Encryption:              Disabled
Cluster health:                     Probe disabled
nslookup -norecurse clustermesh-apiserver.kube-system.svc.cluster.local

Server:         10.96.0.10
Address:        10.96.0.10#53

Name:   clustermesh-apiserver.kube-system.svc.cluster.local
Address: 10.99.176.216
ping $(sudo cilium-dbg service list get \
-o jsonpath='{[?(@.spec.flags.name=="clustermesh-apiserver")].spec.backend-addresses[0].ip}') -c 5

PING 10.244.1.92 (10.244.1.92) 56(84) bytes of data.
64 bytes from 10.244.1.92: icmp_seq=1 ttl=63 time=1.19 ms
64 bytes from 10.244.1.92: icmp_seq=2 ttl=63 time=0.587 ms
64 bytes from 10.244.1.92: icmp_seq=3 ttl=63 time=0.697 ms
64 bytes from 10.244.1.92: icmp_seq=4 ttl=63 time=0.634 ms
64 bytes from 10.244.1.92: icmp_seq=5 ttl=63 time=0.399 ms

--- 10.244.1.92 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4076ms
rtt min/avg/max/mdev = 0.399/0.702/1.193/0.264 ms

Install the ingress controller outside of your cluster

Copy the /etc/kubernetes/admin.conf kubeconfig file from the control plane server to this server and store it in the root user’s home directory. The ingress controller will use this to connect to the Kubernetes API.

sudo mkdir -p /root/.kube
sudo cp admin.conf /root/.kube/config
sudo chown -R root:root /root/.kube
kubectl create configmap -n default haproxy-kubernetes-ingress

HAProxy Kubernetes Ingress Controller is compatible with a specific version of HAProxy. Install the HAProxy package on your Linux distribution based on the table below. For Ubuntu and Debian, follow the install steps at haproxy.debian.net

Ingress controller version Compatible HAProxy version
1.11 2.8
1.10 2.7
1.9 2.6
1.8 2.5
1.7 2.4

In my case I use Ingress controller version 1.11 and HAProxy version 2.8:

curl https://haproxy.debian.net/bernat.debian.org.gpg \
      | gpg --dearmor > /usr/share/keyrings/haproxy.debian.net.gpg
echo deb "[signed-by=/usr/share/keyrings/haproxy.debian.net.gpg]" \
      http://haproxy.debian.net bookworm-backports-2.8 main \
      > /etc/apt/sources.list.d/haproxy.list

apt-get update
apt-get install haproxy=2.8.\*

Stop and disable the HAProxy service.

sudo systemctl stop haproxy
sudo systemctl disable haproxy

Call the setcap command to allow HAProxy to bind to ports 80 and 443:

sudo setcap cap_net_bind_service=+ep /usr/sbin/haproxy

Download the ingress controller from the project’s GitHub Releases page Extract it and then copy it to the /usr/local/bin directory.

wget https://github.com/haproxytech/kubernetes-ingress/releases/download/v1.11.3/haproxy-ingress-controller_1.11.3_Linux_x86_64.tar.gz

tar -xzvf haproxy-ingress-controller_1.11.3_Linux_x86_64.tar.gz
sudo cp ./haproxy-ingress-controller /usr/local/bin/

Create the file /lib/systemd/system/haproxy-ingress.service and add the following to it:

cat << EOF > /lib/systemd/system/haproxy-ingress.service
[Unit]
Description="HAProxy Kubernetes Ingress Controller"
Documentation=https://www.haproxy.com/
Requires=network-online.target
After=network-online.target
[Service]
Type=simple
User=root
Group=root
ExecStart=/usr/local/bin/haproxy-ingress-controller --external --default-ssl-certificate=ingress-system/default-cert --configmap=default/haproxy-kubernetes-ingress --program=/usr/sbin/haproxy --disable-ipv6 --ipv4-bind-address=0.0.0.0 --http-bind-port=80 --https-bind-port=443  --ingress.class=ingress-public
ExecReload=/bin/kill --signal HUP $MAINPID
KillMode=process
KillSignal=SIGTERM
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF

Enable and start the service.

sudo systemctl enable haproxy-ingress
sudo systemctl start haproxy-ingress

Demo Aapp

nano demo-app.yaml
---
apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
  annotations:
    ingressclass.kubernetes.io/is-default-class: "false"
  labels:
    app.kubernetes.io/instance: ingress-public
  name: ingress-public
spec:
  controller: haproxy.org/ingress-controller/ingress-public
---
apiVersion: apps/v1
kind: Deployment
metadata:
 labels:
   run: app
 name: app
 namespace: default
spec:
 replicas: 5
 selector:
   matchLabels:
     run: app
 template:
   metadata:
     labels:
       run: app
   spec:
     containers:
     - name: app
       image: jmalloc/echo-server
       ports:
       - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
 labels:
   run: app
 name: app
 namespace: default
spec:
 selector:
   run: app
 ports:
 - name: port-1
   port: 80
   protocol: TCP
   targetPort: 8080
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
 name: test-ingress
 namespace: default
spec:
  ingressClassName: ingress-public
  rules:
  - host: "example.com"
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app
            port:
              number: 80
kubectl apply -f demo-app.yaml
cat /tmp/haproxy-ingress/etc/haproxy.cfg
...
backend default_app_port-1
  mode http
  balance roundrobin
  option forwardfor
  no option abortonclose
  default-server check
  server SRV_1 10.244.1.105:8080 enabled

egrep -r "example" /tmp/haproxy-ingress/
/tmp/haproxy-ingress/etc/maps/host.map:example.com                      example.com
/tmp/haproxy-ingress/etc/maps/path-prefix.map:example.com/                      default_app_port-1
sudo nano /etc/hosts
127.0.0.1 example.com
curl http://example.com
Request served by app-84bdb7868d-hxwb7

GET / HTTP/1.1

Host: example.com
Accept: */*
User-Agent: curl/8.1.2
X-Forwarded-For: 192.168.56.7