setup minik3s for the single host

mini-k3s-default.sh

#!/bin/bash
cat > /etc/default/k3s <<EOF
GOGC=10
EOF
chmod 600 /etc/default/k3s

K3S_CHANNEL=v1.26

# --disable-helm-controller
curl -sfL https://get.k3s.io | \
    INSTALL_K3S_CHANNEL=${K3S_CHANNEL} \
    K3S_TOKEN=SUSERancherGC \
    sh -s - server \
    --disable-cloud-controller \
    --disable-network-policy

# k3s process RSS memory
ps eo user,pid,vsz,rss,%cpu,%mem $(pgrep k3s) | tail -1 | awk '{$4=int($4/1024)"M";}{ print $4;}'
ps eo user,pid,vsz,rss,%cpu,%mem $(pgrep -f k3s) | tail -n +2 | awk '{$4=int($4/1024)"M";}{ print $4;}'

# k3s cgroups memory
systemd-cgls --no-pager /system.slice/k3s.service
systemd-cgtop -m -n 3 /system.slice/k3s.service | tail -1 | awk -F ' ' '{print $4}'

# kube-pods cgroups memory
systemd-cgls --no-pager /kubepods.slice
systemd-cgtop -m -n 3 /kubepods.slice | head -1 | awk -F ' ' '{print $4}'

# drop cgroup page cache
echo 1 > /proc/sys/vm/drop_caches

# check cgroup version
# for cgroup v2, the output is cgroup2fs
# fcgroup v1, the output is tmpfs
stat -fc %T /sys/fs/cgroup/

# Process VmRSS(RSS) = Process RssAnon + Process RssFile + Process RssShmem
cat /proc/$(pgrep metrics-server)/status | grep VmRSS | awk '{$2=int($2/1024)"M";}{ print $2;}M'
cat /proc/$(pgrep metrics-server)/status | grep RssAnon | awk '{$2=int($2/1024)"M";}{ print $2;}M'
cat /proc/$(pgrep metrics-server)/status | grep RssFile | awk '{$2=int($2/1024)"M";}{ print $2;}M'

# ubuntu 22.04, kernel 5.19.0-1025-aws, cgroupv2
# cgroupv2 memory: https://docs.kernel.org/admin-guide/cgroup-v2.html#memory
cat /sys/fs/cgroup/$(cat /proc/$(pgrep metrics-server)/cgroup | awk -F ':' '{print $3}')/memory.current | awk '{$1=int($1/1024/1024)"M";}{ print $1;}'

# sle micro 5.3, kernel 5.14.21-150400.24.41-default, cgroupv1
# cgroupv1 memory: https://docs.kernel.org/admin-guide/cgroup-v1/memory.html#accounting-details
# check https://docs.kernel.org/admin-guide/cgroup-v1/memory.html#usage-in-bytes
cat /sys/fs/cgroup/memory/$(cat /proc/$(pgrep metrics-server)/cgroup | grep memory | awk -F ':' '{print $3}')/memory.usage_in_bytes | awk '{$1=int($1/1024/1024)"M";}{ print $1;}'
# check https://docs.kernel.org/admin-guide/cgroup-v1/memory.html#stat-file
cat /sys/fs/cgroup/memory/$(cat /proc/$(pgrep metrics-server)/cgroup | grep memory | awk -F ':' '{print $3}')/memory.stat | grep "^rss " | awk '{$2=int($2/1024/1024)"M";}{ print $2;}'

mini-k3s-test.sh

#!/bin/bash
#
# test with v1.19.5+k3s1
#

mkdir -p /opt/cni/bin
curl -L https://github.com/containernetworking/plugins/releases/download/v0.9.0/cni-plugins-linux-amd64-v0.9.0.tgz | tar xvz -C /opt/cni/bin/

mkdir -p /etc/cni/net.d
cat >/etc/cni/net.d/10-mynet.conf <<EOF
{
    "cniVersion": "0.3.1",
    "name": "mynet",
    "type": "bridge",
    "bridge": "mynet0",
    "isDefaultGateway": true,
    "forceAddress": false,
    "ipMasq": true,
    "hairpinMode": true,
    "ipam": {
        "type": "host-local",
        "subnet": "10.42.0.0/24"
    }
}
EOF

cat >/etc/cni/net.d/99-loopback.conf <<EOF
{
    "cniVersion": "0.3.1",
    "name": "lo",
    "type": "loopback"
}
EOF

#--disable-scheduler \

./k3s server \
        --disable servicelb,traefik,local-storage,metrics-server,coredns \
        --disable-cloud-controller \
        --disable-network-policy \
        --flannel-backend none \
        --disable-kube-proxy \
        --kube-apiserver-arg profiling=false \
        --kube-apiserver-arg default-watch-cache-size=10 \
        --kube-apiserver-arg enable-priority-and-fairness=false \
        --kube-controller-manager-arg controllers=*,-cronjob,-daemonset,-statefulset,-job,-horizontalpodautoscaling \
        --kube-controller-manager-arg concurrent-deployment-syncs=1 \
        --kube-controller-manager-arg concurrent-endpoint-syncs=1 \
        --kube-controller-manager-arg concurrent-gc-syncs=2 \
        --kube-controller-manager-arg concurrent-resource-quota-syncs=1 \
        --kube-controller-manager-arg concurrent-namespace-syncs=2 \
        --kube-controller-manager-arg concurrent-replicaset-syncs=1 \
        --kube-controller-manager-arg concurrent-service-endpoint-syncs=1 \
        --kube-controller-manager-arg concurrent-service-syncs=1 \
        --kube-controller-manager-arg concurrent-serviceaccount-token-syncs=1 \
        --kube-controller-manager-arg concurrent-statefulset-syncs=1 \
        --kube-controller-manager-arg concurrent-ttl-after-finished-syncs=1 \
        --kube-controller-manager-arg concurrent_rc_syncs=1 \
        --kube-controller-manager-arg enable-taint-manager=false \
        --kube-controller-manager-arg profiling=false \
        --kube-controller-manager-arg leader-elect=false \
        --kubelet-arg enable-server=false