Document: Official document, 中文文档, Blog

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Introduction

Build a kubernetes HA cluster for a production environment.

• Each node will be configured with an ipvs proxy for masters LB, so we needn't haproxy or keepalived any more.
• Then run a lvscare as a staic pod to check apiserver is aviliable. /etc/kubernetes/manifests/sealyun-lvscare.yaml
• If any master is down, lvscare will remove the ipvs realserver, when master recover it will add it back.
• Sealos will send package and apply install commands, so we needn't ansible.

✨ Supported Environment

Linux Distributions, CPU Architecture

• Debian 9+, x86_64/ arm64
• Ubuntu 16.04， 18.04， 20.04 , x86_64/ arm64
• Centos/RHEL 7.6+, x86_64/ arm64
• 99% systemd manage linux system， x86_64/ arm64
• Kylin arm64

kubernetes Versions

• 1.16+
• 1.17+
• 1.18+
• 1.19+
• 1.20+
• 1.21+
• 1.22+
• 1.23+

Looking for more supported versions, sealyun.com.

Requirements and Recommendations

• Minimum resource requirements

  • 2 vCpu
  • 4G RAM
  • 40G+ Storage

• OS requirements

  • SSH can access to all nodes.
  • These nodes have unique host names that meet the hostname requirements for kubernetes.
  • Time synchronization for all nodes.
  • Network Iface name is unique, it is recommended to change it to a standard NIC name, such as (eth.|en.|em.*).
  • Kubernetes1.20+, use containerd for default cri. user should not to install containerd or docker-ce. sealos will do it
  • Kubernetes1.19-, use docker for default cri. user should not to install docker-ce. sealos will do it for you

• Networking and DNS requirements：

  • Make sure the DNS address in /etc/resolv.conf is available. Otherwise, it may cause some issues of DNS in cluster。
  • If you use Ali cloud or Huawei cloud host to deploy. The default pod segment will conflict with AliCloud's dns segment, it is recommended to customize the pod segment by specifying --podcidr during init.
  • Sealos disables the firewall by default ，If you need to open the firewall, it is recommended to release the relevant ports manually.

• Kernel requirements:

  • The cni component requires a kernel version of not less than 5.4 when selecting cilium

Tips

• If you use Tencent Cloud Hosting to deploy, calico's IPIP rules are disabled by default, and you need to change to VXLAN rules to use it properly.

🚀 Quick Start

Environmental information

Hostname	IP Address
master0	192.168.0.2
master1	192.168.0.3
master2	192.168.0.4
node0	192.168.0.5

Server password：123456

kubernetes .0, the version is not recommended for production environment!!!

Just prepare the server and execute the following command on any server

# download and install sealos, sealos is a binary tool of golang, just download and copy directly to the bin directory, the release page can also be downloaded
wget -c https://sealyun-home.oss-cn-beijing.aliyuncs.com/sealos/latest/sealos && \
    chmod +x sealos && mv sealos /usr/bin

# download offline resource pack
wget -c https://sealyun.oss-cn-beijing.aliyuncs.com/05a3db657821277f5f3b92d834bbaf98-v1.22.0/kube1.22.0.tar.gz

# Install a three-master kubernetes cluster
sealos init --passwd '123456' \
	--master 192.168.0.2  --master 192.168.0.3  --master 192.168.0.4  \
	--node 192.168.0.5 \
	--pkg-url /root/kube1.22.0.tar.gz \
	--version v1.22.0

Parameter meaning

parameter	meaning	example
passwd	server password	123456
master	k8s master IP Address	192.168.0.2
node	k8s node IP Address	192.168.0.3
pkg-url	offline resource package address, support downloading to local or a remote address	/root/kube1.22.0.tar.gz
version	Resource pack Corresponding version	v1.22.0

add master

🐳 → sealos join --master 192.168.0.6 --master 192.168.0.7
🐳 → sealos join --master 192.168.0.6-192.168.0.9  # or multiple consecutive IPs

add node

🐳 → sealos join --node 192.168.0.6 --node 192.168.0.7
🐳 → sealos join --node 192.168.0.6-192.168.0.9  # or multiple consecutive IPs

delete the specified master

🐳 → sealos clean --master 192.168.0.6 --master 192.168.0.7
🐳 → sealos clean --master 192.168.0.6-192.168.0.9  # or multiple consecutive IPs

Delete the specified node

🐳 → sealos clean --node 192.168.0.6 --node 192.168.0.7
🐳 → sealos clean --node 192.168.0.6-192.168.0.9  # or multiple consecutive IPs

clean up the cluster

🐳 → sealos clean --all

✅ Feature

• Support ARM version offline package, v1.20 version offline package supports containerd integration, completely abandon docker
• 99 years certificate, support cluster backup and upgrade
• No dependency on ansible haproxy keepalived, a binary tool, 0 dependency
• Offline installation, different versions of kubernetes download corresponding to different versions Resource pack, Offline package contains all binary files configuration files and images
• High-availability local LIB implemented through ipvs, which takes up less resources, is stable and reliable, and is similar to the implementation of kube-proxy
• Almost compatible with all environments that support systemd x86_64 architecture
• Easily add and delete cluster nodes
• Thousands of users use sealos in the online environment, which is stable and reliable
• The resource pack is placed on Alibaba Cloud OSS, so you don’t have to worry about network speed anymore

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