Hackfi

• install containerd and remove docker

systemctl stop docker
dnf remove docker-ce -y

dnf install containerd -y

sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml
systemctl start containerd
systemctl enable containerd

• edit /var/lib/kubelet/kubeadm-flags.env add below

KUBELET_KUBEADM_ARGS="--pod-infra-container-image=k8s.gcr.io/pause:3.5 --container-runtime=remote --container-runtime-endpoint=unix:///run/containerd/containerd.sock"

OR
KUBELET_KUBEADM_ARGS="--container-runtime=remote --container-runtime-endpoint=unix:///run/containerd/containerd.sock"

• edit /etc/crictl.yaml to remove crictl warning message

echo 'runtime-endpoint: unix:///run/containerd/containerd.sock' > /etc/crictl.yaml

systemctl start containerd


#[ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables does not exist
#[ERROR FileContent--proc-sys-net-ipv4-ip_forward]: /proc/sys/net/ipv4/ip_forward contents are not set to 1

lsmod | grep -i netfilter
modprobe br_netfilter

echo 1 > /proc/sys/net/ipv4/ip_forward

echo 'net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1' > /etc/sysctl.d/k8s.conf

Remove CNI binary form /opt/cni/bin/*

rm -rf /opt/cni/bin/*

For Ubuntu 22.04 need to install containernetworking-plugins:

failed to load CNI config list file /etc/cni/net.d/10-calico.conflist: error parsing configuration list: unexpected end of JSON input: invalid cni config: failed to load

apt install containernetworking-plugins

#crontab entry for ubuntu 

@reboot modprobe br_netfilter
@reboot echo 1 > /proc/sys/net/ipv4/ip_forward

Note : weaves CNI had issue with containerd , k8 1.24 I uninstalled it.

It’s working with calico CNI

• For new containerd version above 1.5.9

vi /etc/containerd/config.toml

SystemdCgroup = true

• For Raspberry pi edit /boot/firmware/cmdline.txt and append this line

cgroup_enable=cpuset cgroup_enable=memory

• Kernal 6.12.40-v8+ has some issues with cgroup_enable=memory need to switch to 6.6

root@lp-arm-2:~# cat /proc/cmdline
coherent_pool=1M 8250.nr_uarts=0 snd_bcm2835.enable_headphones=0 cgroup_disable=memory .....

grep memory /proc/cgroups
dmesg | grep 'Kernel command line'
strings /boot/kernel8.img | grep cgroup_disable

• Ubuntu 22.04 kubelet SandboxChanged issue fixed set SystemdCgroup = true in /etc/containerd/config.toml : https://github.com/kubernetes/kubernetes/issues/110177#issuecomment-1161647736

• https://kubernetes.io/docs/concepts/extend-kubernetes/compute-storage-net/network-plugins/
• https://kubernetes.io/docs/tasks/administer-cluster/migrating-from-dockershim/troubleshooting-cni-plugin-related-errors/
• https://github.com/weaveworks/weave/issues/3942
• https://github.com/weaveworks/weave/issues/3936
• https://github.com/awslabs/amazon-eks-ami/blob/master/scripts/install-worker.sh

kubectl drain ip-10-222-110-231.eu-west-1.compute.internal --delete-emptydir-data="true" --ignore-daemonsets="true" --timeout="15m" --force

kubectl get nodes --label-columns beta.kubernetes.io/instance-type --label-columns beta.kubernetes.io/capacity-type -l role=worker

• deleted pod automatically

#send output to env_output.tail
for i in $(cat qa.node); 
do echo "draining node : $i"
kubectl drain $i  --delete-emptydir-data="true" --ignore-daemonsets="true" --timeout="15m" --force >> env_output.tail 2>&1
echo "completed node : $i"
done

#read env_output.tail to delete pod
while(true)
do
pods=$(tail -n 20 env_output.tail | grep "error when evicting" | cut -d '(' -f1 | awk -F 'evicting' '{print $2}' | uniq | awk '{print $1,$2,$3}')
echo pods: $pods
apod=$(echo "$pods" | sed 's/"//g')
echo apod: $apod
echo "kubectl delete $apod"
kubectl delete $apod
sleep 5
done

#namespace=$(kubeclt get ns | tr "\n" " ")
namespace="abc xyz"

for ns in $namespace
do
    deploy=$(kubectl get deploy -n $ns | grep -v '0/' | awk '{print $1}' | sed 1d)
    for i in $deploy
    do
        kubectl -n $ns patch deployment $i -p '{"spec": {"template": {"spec": {"containers": [{"name": "'$i'","resources": { "requests": {"cpu": "100m"}}}]}}}}'
        echo "patched : $i ns=$ns"
    done
done

https://faun.pub/kubectl-commands-cheatsheet-43ce8f13adfb