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Published 20 hours ago • verified publisher icon valentin2105
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Recipe to deploy a production Kubernetes cluster.

Kubernetes-Saltstack provide an easy way to deploy H/A Kubernetes Cluster using Salt.

Features

  • Cloud-provider agnostic
  • Support high-available clusters
  • Use the power of Saltstack
  • Made for systemd based Linux systems
  • Layer 3 networking by default (Calico)
  • CoreDNS as internal DNS resolver
  • Highly Composable (CNI, CRI, Add-ons)
  • Integrated add-ons (Helm, CoreDNS, MetalLB, Dashboard, Nginx-Ingress, ...)
  • RBAC & TLS by default
  • Support IPv6

Getting started

I. Generate CA and TLS certificates using CfSSL

Let's clone the git repo on Salt-master and create CA & certificates on the k8s-certs/ directory using CfSSL tools:

git clone https://github.com/valentin2105/Kubernetes-Saltstack.git /srv/salt
ln -s /srv/salt/pillar /srv/pillar

wget -q --show-progress --https-only --timestamping \
   https://pkg.cfssl.org/R1.2/cfssl_linux-amd64 \
   https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64

chmod +x cfssl_linux-amd64 cfssljson_linux-amd64
sudo mv cfssl_linux-amd64 /usr/local/bin/cfssl
sudo mv cfssljson_linux-amd64 /usr/local/bin/cfssljson
IMPORTANT Point

Because we generate our own CA and certificates for the cluster,

You MUST put every hostnames and IPs of the Kubernetes cluster (master & workers) in the certs/kubernetes-csr.json (hosts field).

You can also modify the certs/*json files to match your cluster-name / country. (optional)

You can use either public or private names, but they must be registered somewhere (DNS provider, internal DNS server, /etc/hosts file) or use IP records instead of names.

cd /srv/salt/k8s-certs
cfssl gencert -initca ca-csr.json | cfssljson -bare ca

# !!!!!!!!!
# Don't forget to edit kubernetes-csr.json before this point !
# !!!!!!!!!

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -profile=kubernetes \
  kubernetes-csr.json | cfssljson -bare kubernetes

chown salt: /srv/salt/k8s-certs/ -R

After that, edit the pillar/cluster_config.sls to tweak your future Kubernetes cluster :

kubernetes:
  version: v1.16.1
  domain: cluster.local

  master:
    count: 1
    hostname: <ValidHostname-or-IP>
    ipaddr: 10.240.0.10

    etcd:
      version: v3.3.12
    encryption-key: '0Wh+uekJUj3SzaKt+BcHUEJX/9Vo2PLGiCoIsND9GyY='

  pki:
    enable: false
    host: master01.domain.tld
    wildcard: '*.domain.tld'

  worker:
    runtime:
      provider: docker
      docker:
        version: 18.09.9
        data-dir: /dockerFS
    networking:
      cni-version: v0.7.1
      provider: calico
      calico:
        version: v3.9.0
        cni-version: v3.9.0
        calicoctl-version: v3.9.0
        controller-version: 3.9-release
        as-number: 64512
        token: hu0daeHais3a--CHANGEME--hu0daeHais3a
        ipv4:
          range: 192.168.0.0/16
          nat: true
          ip-in-ip: true
        ipv6:
          enable: false
          nat: true
          interface: eth0
          range: fd80:24e2:f998:72d6::/64

  global:
    clusterIP-range: 10.32.0.0/16
    helm-version: v2.14.3
    dashboard-version: v2.0.0-beta4
    coredns-version: 1.6.4 
    admin-token: Haim8kay1rar--CHANGEME--Haim8kay11ra
    kubelet-token: ahT1eipae1wi--CHANGEME--ahT1eipa1e1w
    metallb: 
      enable: false
      version: v0.8.1
      protocol: layer2
      addresses: 10.100.0.0/24
    nginx-ingress:
      enable: false 
      version: 0.26.1
      service-type: LoadBalancer
    cert-manager:
      enable: false
      version: v0.11.0
Don't forget to change Master's hostname & Tokens using pwgen for example !

If you want to enable IPv6 on pod's side, you need to change kubernetes.worker.networking.calico.ipv6.enable to true.

II. Cluster deployment

To deploy your Kubernetes cluster using this formula, you first need to setup your Saltstack master/Minion.

You can use Salt-Bootstrap or Salt-Cloud to enhance the process.

The configuration is done to use the Salt-master as the Kubernetes master.

You can have them as different nodes if needed but the post_install/script.sh require kubectl and access to the pillar files.

The recommended configuration is :

  • one or three Kubernetes-master (Salt-master & minion)

  • one or more Kubernetes-workers (Salt-minion)

The Minion's roles are matched with Salt Grains (kind of inventory), so you need to define theses grains on your servers :

If you want a small cluster, a master can be a worker too.

# Kubernetes masters
cat << EOF > /etc/salt/grains
role: k8s-master
EOF

# Kubernetes workers
cat << EOF > /etc/salt/grains
role: k8s-worker
EOF

# Kubernetes master & workers
cat << EOF > /etc/salt/grains
role: 
  - k8s-master
  - k8s-worker
EOF

service salt-minion restart

After that, you can apply your configuration with a (highstate) :

# Apply Kubernetes master configurations :
~ salt -G 'role:k8s-master' state.highstate 

~ kubectl get componentstatuses
NAME                 STATUS    MESSAGE              ERROR
scheduler            Healthy   ok
controller-manager   Healthy   ok
etcd-0               Healthy   {"health": "true"}
etcd-1               Healthy   {"health": "true"}
etcd-2               Healthy   {"health": "true"}

# Apply Kubernetes worker configurations :
~ salt -G 'role:k8s-worker' state.highstate

~ kubectl get nodes
NAME           STATUS   ROLES    AGE     VERSION   OS-IMAGE                       KERNEL-VERSION           CONTAINER-RUNTIME
k8s-worker01   Ready    <none>   3h56m   v1.16.1   Ubuntu 18.04.3 LTS             4.15.0-58-generic        docker://18.9.9
k8s-worker02   Ready    <none>   3h56m   v1.16.1   Ubuntu 18.04.3 LTS             4.15.0-58-generic        docker://18.9.9
k8s-worker03   Ready    <none>   91m     v1.16.1   Debian GNU/Linux 10 (buster)   4.19.0-6-cloud-amd64     docker://18.9.9
k8s-worker04   Ready    <none>   67m     v1.16.1   Fedora 30 (Cloud Edition)      5.2.18-200.fc30.x86_64   docker://18.9.9

# Deploy Calico and Add-ons :
~  /opt/kubernetes/post_install/setup.sh

~# kubectl get pod --all-namespaces
cert-manager           pod/cert-manager-55c44f98f-vmpcm                     1/1     Running     
cert-manager           pod/cert-manager-cainjector-576978ffc8-w7m5j         1/1     Running     
cert-manager           pod/cert-manager-webhook-c67fbc858-tjcvm             1/1     Running     
default                pod/debug-85d7f9799-dtc6c                            1/1     Running
kube-system            pod/calico-kube-controllers-5979855b8-vdpvw          1/1     Running
kube-system            pod/calico-node-h7n58                                1/1     Running
kube-system            pod/calico-node-jl4fc                                1/1     Running
kube-system            pod/calico-node-tv5cq                                1/1     Running
kube-system            pod/calico-node-xxbgh                                1/1     Running
kube-system            pod/coredns-7c7c6c44bf-4lxn4                         1/1     Running
kube-system            pod/coredns-7c7c6c44bf-t9g7v                         1/1     Running
kube-system            pod/tiller-deploy-6966cf57d8-jpf5k                   1/1     Running
kubernetes-dashboard   pod/dashboard-metrics-scraper-566cddb686-mf8xn       1/1     Running
kubernetes-dashboard   pod/kubernetes-dashboard-7b5bf5d559-25cdb            1/1     Running
metallb-system         pod/controller-6bcfdfd677-g9s6f                      1/1     Running
metallb-system         pod/speaker-bmx5p                                    1/1     Running
metallb-system         pod/speaker-g8cqr                                    1/1     Running
metallb-system         pod/speaker-mklzd                                    1/1     Running
metallb-system         pod/speaker-xmhkm                                    1/1     Running
nginx-ingress          pod/nginx-ingress-controller-5dcb7b4488-b68zj        1/1     Running
nginx-ingress          pod/nginx-ingress-controller-5dcb7b4488-n7kwc        1/1     Running
nginx-ingress          pod/nginx-ingress-default-backend-659bd647bd-5l2km   1/1     Running

III. Add nodes afterwards

If you want add a node on your Kubernetes cluster, just add the new Hostname and IPs on kubernetes-csr.json and run theses commands to regenerate your cluster certificates :

cd /srv/salt/k8s-certs

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -profile=kubernetes \
  kubernetes-csr.json | cfssljson -bare kubernetes

# Reload k8s components on Master and Workers.
salt -G 'role:k8s-master' state.highstate
salt -G 'role:k8s-worker' state.highstate

The highstate configure automatically new workers (if it match the k8s-worker role in Grains).

  • Tested on Debian, Ubuntu and Fedora.
  • You can easily upgrade software version on your cluster by changing values in pillar/cluster_config.sls and apply a highstate.
  • This configuration use ECDSA certificates (you can switch to rsa in certs/*.json).
  • You can change IPv4 IPPool, enable IPv6, change IPv6 IPPool, enable IPv6 NAT (for no-public networks), change BGP AS number, Enable IPinIP (to allow routes sharing between subnets).
  • If you use salt-ssh or salt-cloud you can quickly scale new workers.

Support me on Patreon

Help me out for a couple of :beers:!

https://www.patreon.com/ValentinOuvrard

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Recipe to deploy a production Kubernetes cluster.

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