Docker

• Registry 필요

K8s

• Swap을 꺼야 함 (컨테이너에 메모리 제한이 가능한데, 스왑이 켜져있으면 메모리 제한 이상 사용시 스왑을 땡겨오는 증상이 있었다고 함)

sudo apt-get install -y apt-transport-https ca-certificates curl
# If the directory `/etc/apt/keyrings` does not exist, it should be created before the curl command, read the note below.
# sudo mkdir -p -m 755 /etc/apt/keyrings
curl -fsSL <https://pkgs.k8s.io/core:/stable:/v1.31/deb/Release.key> | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
# This overwrites any existing configuration in /etc/apt/sources.list.d/kubernetes.list
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] <https://pkgs.k8s.io/core:/stable:/v1.31/deb/> /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

자원 분리를 위해 cgroup을 사용해야 함

• SystemD 도 unit마다 cgroup을 만듦
• SystemD는 단일 cgroup을 권장함 (다른데서 cgroup 기능을 사용하면 잠재적인 문제가 생길 수 있다고 함. ⇒ CPU, 메모리가 빡빡할때 사용률 제한으로 밸런스를 잡을 수 있는데, 두곳에서 cgroup을 사용하면 문제 발생 가능)
• 그러므로, Systemd (systemctl)이 있는 시스템에서는 cgroupfs말고 systemd를 사용해야 함.

cgroup ≠ namespace

# sysctl params required by setup, params persist across reboots
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
EOF

# Apply sysctl params without reboot
sudo sysctl --system

sudo mv /etc/containerd/config.toml /etc/containerd/config.toml.bak

cri = container runtime interface

containerd config default > /etc/containerd/config.toml

  GNU nano 7.2                                                                                            /etc/containerd/config.toml.bak                                                                                                     
#   Copyright 2018-2022 Docker Inc.

#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at

#       <http://www.apache.org/licenses/LICENSE-2.0>

#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

disabled_plugins = ["cri"]

#root = "/var/lib/containerd"
#state = "/run/containerd"
#subreaper = true
#oom_score = 0

#[grpc]
#  address = "/run/containerd/containerd.sock"
#  uid = 0
#  gid = 0

#[debug]
#  address = "/run/containerd/debug.sock"
#  uid = 0
#  gid = 0
#  level = "info"