Difference between revisions of "Kubernetes"

Latest revision as of 22:07, 8 August 2021

Kubernetes @ FIXME

Information

• Endpoint: k8s.fixme.ch
• Credentials are available in file k8s:/etc/kubernetes/admin.conf.
• Currently running on Bellatrix
• Backup: https://git.fixme.ch/Comite/fixme-kube-backup (restricted for secret access)

Services

• Some services that are deployed on our instance
  • Chat
  • Etherpad
  • Power monitoring
  • Fablab wiki
  • Led API endpoint
  • Trigger
  • MQTT gateway
  • gitlab: ongoing

Add your own Service

A service is composed of:

• A deployment
• A service
• An ingress controller

at minimum

SSL

• We use cert-manager to manage LetsEncrypt certs, you only need to add this annotation to your Ingress Controller for it to manage your cert,

ubuntu@k8s:~$ k edit -n mattermost ingress/mattermost-ingress
[...]
metadata:
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt
[...]

Debug

Access impossible

Sometimes the eth interface is in the sauce (to investigate), you have to reconfigure it.

ubuntu@k8s:~$ sudo ip addr add 62.220.135.219/32 dev ens6

It should look like this

ubuntu@k8s:~$ ip -4 a show ens6 
2: ens6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    inet 62.220.135.205/26 brd 62.220.135.255 scope global ens6
       valid_lft forever preferred_lft forever
    inet 62.220.135.219/32 scope global ens6
       valid_lft forever preferred_lft forever

Certificate expiration

Sometimes K8S is in the sauce, something like this might help regenerate the certs

# Service state
systemctl stop kubelet.service
systemctl restart docker.service

# Backup
rsync -av /etc/kubernetes/ /root/kubernetes-$(date +%s)/
rsync -av /var/lib/etcd/ /root/etcd-$(date +%s)/

cd /etc/kubernetes
rm {admin.conf,controller-manager.conf,kubelet.conf,scheduler.conf}

cd /etc/kubernetes/pki
rm {apiserver.crt,apiserver-etcd-client.key,apiserver-kubelet-client.crt,front-proxy-ca.crt,front-proxy-client.crt,front-proxy-client.key,front-proxy-ca.key,apiserver-kubelet-client.key,apiserver.key,apiserver-etcd-client.crt}

# Regen certificates
cd
kubeadm init phase certs all --apiserver-advertise-address 62.220.135.205 --ignore-preflight-errors=all
kubeadm init phase kubeconfig all
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

# Check states
kubeadm join 62.220.135.205:6443 --token XXX --discovery-token-ca-cert-hash YYY --ignore-preflight-errors=all
kubectl get nodes
kubectl get all