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This article will explain in detail how to install CoreOS. The editor thinks it is very practical, so I share it with you for reference. I hope you can get something after reading this article.

CoreOS is a lightweight operating system based on Linux kernel, which is born for the infrastructure construction of computer cluster, focusing on automation, easy deployment, security, reliability and scale. As an important member of Docker ecosystem, CoreOS has been paid more and more attention by major cloud service providers.

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CoreOS claims to minimize the customized version of linux system:

Linux kernel

There are two ROOT partitions required for Linux to run. One is used as the boot partition and the other is used as the update partition. After the update is completed, the system restarts automatically. The current machine does not need to be removed from the load cluster. In order to ensure that other applications will not be interrupted, the use of disk, network and other IO during the update process will be restricted through Linux cgroup.

Systemd

As the default system and service manager, its excellent features are:

Support parallel tasks; use both socket and D-Bus bus activation services; start daemons on demand (daemon); use Linux's cgroups to monitor processes; support snapshots and system recovery; maintain mount points and automatic mount points; and precisely control services based on dependencies.

The root partition is designed to be read-only

Root partitions are designed to be read-only to ensure data consistency and update availability

Isolation of CPU, IO and other resources

Naturally, to sacrifice a container (Container), CoreOS wisely uses Docker as a container manager to build and publish applications. From this level, an application is actually a container.

The etcd component is responsible for service discovery and configuration sharing

Raft distributed consistency protocol algorithm is adopted to undertake the use of service communication between components. Naturally, the scalability of applications and services between containers (Container) is very simple. It supports clustering at the genetic level, and of course, you can also interpret it as the support of a cloud environment.

One: prepare the SSH public / private key or password

SSH public key / private key creation: execute ssh-keygen on other linux clients: [root@localhost ~] # ssh-keygenGenerating public/private rsa key pair.Enter file in which to save the key (/ root/.ssh/id_rsa): Created directory'/ root/.ssh'.Enter passphrase (empty for no passphrase): Enter same passphrase again:Your identification has been saved in / root/.ssh/id_rsa.Your public key has been saved in / root/.ssh/id_rsa. Pub.The key fingerprint is:d3:b5:fe:05:81:55:4b:6c:be:08:aa:28:7c:0d:e4:9d root@localhost.localdomainThe key's randomart image is:+-- [RSA 2048]-+ | oo. | | o.o. | | o +. | |. . O. O | | o. S o o o. | | o E o. . O | |. +. . . | | o o o. . | | o. | the steps to be selected are +-+. Enter is completed by default. Then id_rsa id_rsa.pub2 files are generated under the ~ / .ssh / of the current user, and the encryption string in id_rsa.pub is pasted to the corresponding value of the next key version cloud-config.yaml file ssh-authorized-keys.

Password making: execute on other linux clients:

[root@localhost ~] # openssl passwd-1 > 1234.txtPassword: [enter password] Verifying-Password: [enter password] [root@localhost ~] # [root@localhost ~] # cat 1234.txt$1 $ywWEh28N$JPwtTtm54yxmEDNegE5.Z0 paste the encryption string in 1234.txt to the corresponding value of the next password version cloud-config.yaml file passwd.

Two: prepare the cloud-config.yaml file

SSH key version:

# cloud-config

Hostname: myhost

Coreos: etcd: addr: $private_ipv4:4001 peer-addr: $private_ipv4:7001 units:-name: etcd.service command: start-name: fleet.service command: start-name: static.network content: | [Match] Name=eno16777736

[Network] Address=192.168.31.122/24 Gateway=192.168.31.1 DNS=223.5.5.5 DNS=223.6.6.6 users:-name: core ssh-authorized-keys:-ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC8C++zc+hDTWOe5DV+WnEa5/Y+dWN1UDVKX3pBYGHbNCYObpJdYpnaHbe+3NQijt15ZAYqOh7fYJlTx8L08z/bJvmj2n+N0hgO3onB4JsH70bSAL41FPzel7BKFnDlvJ1s3GJahdVzBsrDrCwzM96ofUcImtwji0oWPT3bMApkKa8e2Ty5+WwBuxFKDq/MJVqBK4yJmBnylGzmEyyRnlVpQjsDGdbYjDtHU1ECU+H4oSE7o0cSBQntQeH0ckHMU9cnwnLO8IoHIYad4oY/u+UvLq+58kO85ltioaEmTPkWBIzSB6hP/ghHrQUN/Kf22ECgD5H9CaDDGKHrlwJUZDq1 root@kali

-groups:-sudo-docker

Password version:

# cloud-config

Hostname: myhost

Coreos: etcd: addr: $private_ipv4:4001 peer-addr: $private_ipv4:7001 units:-name: etcd.service command: start-name: fleet.service command: start-name: static.network content: | [Match] Name=eno16777736

[Network] Address=192.168.31.122/24 Gateway=192.168.31.1 DNS=223.5.5.5 DNS=223.6.6.6 users:-name: core passwd:$1 $ywWEh28N$JPwtTtm54yxmEDNegE5.Z0-groups:-sudo-docker

Three: download and install

Now that we have written "cloud-config.yaml", we can download and install CoreOS.

ISO download link: http://stable.release.core-os.net/amd64-usr/current/coreos_production_iso_image.iso

If you start with an ISO disk, you will automatically enter the bash command line and the user is core. Note that the system is only loaded into RAM at this time and is not installed.

If you want to go to the root identity for the current configuration, network, etc., sudo-I.

Download the finished cloud-config.yaml file:

Wget http://192.168.220.137:8080/cloud-config.yaml

Now the preparation work has been completed, if you want to install to the sda hard drive.

[core@server ~] $sudo coreos-install-d / dev/sda-C stable-c. / cloud-config.yaml where:-d specifies the target device-C specified version, here I use stable-c to specify the configuration file, cloud-config.yaml

After executing the installation command, the tool will automatically download the hard disk image of CoreOS from the website and install it on the hard drive. See this sentence to show that the installation is successful: Success! CoreOS stable 835.13.0 is installed on / dev/sda

If there is no accident, you can restart after installation, and you can log in directly through the previously configured SSH client machine and the previously set password. [root@localhost] # ssh core@192.168.31.122The authenticity of host '192.168.220.143 (192.168.220.143)' can't be established.ED25519 key fingerprint is fb:ba:38:e3:bc:14:21:33:0b:0e:46:a3:62:f2:9a:1f.Are you sure you want to continue connecting (yes/no)? YesWarning: Permanently added '192.168.220.143' (ED25519) to the list of known hosts.CoreOS stable (835.13.0) core@myhost ~ $

This is the end of the article on "how to install CoreOS". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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