knowledge/categories/devops.md

AWS

• EC2
• EC2 container
• Cloudfront
• S3
• RDS

CI

• Jenkins
• Gitlab CI
• Travis

Everything is code

• Infrastructure as code
• CI config as code
• Dockerfile

CD

Automation tools

Capistrano

A ruby tool for deploy applications

Chef

What is chef

Chef enables you to manage and scale cloud infrastructure with no downtime or interruptions. Freely move applications and configurations from one cloud to another. Chef is integrated with all major cloud providers including Amazon EC2, VMWare, IBM Smartcloud, Rackspace, OpenStack, Windows Azure, HP Cloud, Google Compute Engine, Joyent Cloud and others.

Chef running a chef-client on each node to be a runner to install applications on remote server. The client can use both pull and push modes to to communication.

More:

• Chef vs ansible: https://www.chef.io/ansible/

Ansible

What is Ansible

Ansible is an IT automation tool. It can configure systems, deploy software, and orchestrate more advanced IT tasks such as continuous deployments or zero downtime rolling updates. Ansible’s goals are foremost those of simplicity and maximum ease of use.

Ansible uses SSH to execute commands on remote server and use RabbitMQ at the transport level by push updates

Puppet

Is also a configuration management tool for servers and designed to install and manage software on existing servers.

Packer

Packer is a tool to allows you build a machine image which contains all preinstalled and configged applications.

Terraform

What is Terraform

Terraform use a declarative language to describe the current state of infrastructure, and there is no server side agent installed.

Terraform is more about declare the resources/services requirements, rather than install softwares and libraries on remote server.

Basic steps

# go to the folder which stores the environment credentials
terraform init # Initialize a new or existing Terraform working directory by creating initial files, loading any remote state, downloading modules, etc.
terraform get # Downloads and installs modules that defined by configuration files
terraform plan # Kind of try run, you will what kind of changes you will have
terraform apply # Apply changes to cluster

HA High Availability

• LB - haproxy
• Keepalived -- vrrp
  • Nginx + Keepalived
• Heartbeat

Network

• IP
  • Private IP Addresses
    • 10.0.0.0 – 10.255.255.255
    • 172.16.0.0 – 172.31.255.255
    • 192.168.0.0 – 192.168.255.255

OSI Model( 7 layers network)

CIDR blocks

Wikipedia

Address	Difference	Mask	Addresses	Relative	Restrictions	Typical use
format	to last address			to class	on a, b, c and d
			A, B, C	(0..255 unless noted)
Decimal	2n
a.b.c.d/32	+0.0.0.0	255.255.255.255	1	20	​1⁄256 C		Host route
a.b.c.d/31	+0.0.0.1	255.255.255.254	2	21	​1⁄128 C	d = 0 ... (2n) ... 254	Point to point links (RFC 3021)
a.b.c.d/30	+0.0.0.3	255.255.255.252	4	22	​1⁄64 C	d = 0 ... (4n) ... 252	Point to point links (glue network)
a.b.c.d/29	+0.0.0.7	255.255.255.248	8	23	​1⁄32 C	d = 0 ... (8n) ... 248	Smallest multi-host network
a.b.c.d/28	+0.0.0.15	255.255.255.240	16	24	​1⁄16 C	d = 0 ... (16n) ... 240	Small LAN
a.b.c.d/27	+0.0.0.31	255.255.255.224	32	25	⅛ C	d = 0 ... (32n) ... 224
a.b.c.d/26	+0.0.0.63	255.255.255.192	64	26	¼ C	d = 0, 64, 128, 192
a.b.c.d/25	+0.0.0.127	255.255.255.128	128	27	½ C	d = 0, 128	Large LAN
a.b.c.0/24	+0.0.0.255	255.255.255.0	256	28	1 C
a.b.c.0/23	+0.0.1.255	255.255.254.0	512	29	2 C	c = 0 ... (2n) ... 254
a.b.c.0/22	+0.0.3.255	255.255.252.0	1,024	210	4 C	c = 0 ... (4n) ... 252	Small business
a.b.c.0/21	+0.0.7.255	255.255.248.0	2,048	211	8 C	c = 0 ... (8n) ... 248	Small ISP/ large business
a.b.c.0/20	+0.0.15.255	255.255.240.0	4,096	212	16 C	c = 0 ... (16n) ... 240
a.b.c.0/19	+0.0.31.255	255.255.224.0	8,192	213	32 C	c = 0 ... (32n) ... 224	ISP/ large business
a.b.c.0/18	+0.0.63.255	255.255.192.0	16,384	214	64 C	c = 0, 64, 128, 192
a.b.c.0/17	+0.0.127.255	255.255.128.0	32,768	215	128 C	c = 0, 128
a.b.0.0/16	+0.0.255.255	255.255.0.0	65,536	216	256 C = B
a.b.0.0/15	+0.1.255.255	255.254.0.0	131,072	217	2 B	b = 0 ... (2n) ... 254
a.b.0.0/14	+0.3.255.255	255.252.0.0	262,144	218	4 B	b = 0 ... (4n) ... 252
a.b.0.0/13	+0.7.255.255	255.248.0.0	524,288	219	8 B	b = 0 ... (8n) ... 248
a.b.0.0/12	+0.15.255.255	255.240.0.0	1,048,576	220	16 B	b = 0 ... (16n) ... 240
a.b.0.0/11	+0.31.255.255	255.224.0.0	2,097,152	221	32 B	b = 0 ... (32n) ... 224
a.b.0.0/10	+0.63.255.255	255.192.0.0	4,194,304	222	64 B	b = 0, 64, 128, 192
a.b.0.0/9	+0.127.255.255	255.128.0.0	8,388,608	223	128 B	b = 0, 128
a.0.0.0/8	+0.255.255.255	255.0.0.0	16,777,216	224	256 B = A		Largest IANA block allocation
a.0.0.0/7	+1.255.255.255	254.0.0.0	33,554,432	225	2:00 am	a = 0 ... (2n) ... 254
a.0.0.0/6	+3.255.255.255	252.0.0.0	67,108,864	226	4:00 am	a = 0 ... (4n) ... 252
a.0.0.0/5	+7.255.255.255	248.0.0.0	134,217,728	227	8:00 am	a = 0 ... (8n) ... 248
a.0.0.0/4	+15.255.255.255	240.0.0.0	268,435,456	228	16 A	a = 0 ... (16n) ... 240
a.0.0.0/3	+31.255.255.255	224.0.0.0	536,870,912	229	32 A	a = 0 ... (32n) ... 224
a.0.0.0/2	+63.255.255.255	192.0.0.0	1,073,741,824	230	64 A	a = 0, 64, 128, 192
a.0.0.0/1	+127.255.255.255	128.0.0.0	2,147,483,648	231	128 A	a = 0, 128
0.0.0.0/0	+255.255.255.255	0.0.0.0	4,294,967,296	232	256 A

tools

git

- cherrypick
- rebase
- commit
- checkout
	- checkout -b br com
- push
	- --tags
		- push tags
	- —all
		- push all branchs
	- -f
		- force push
- branch -d xx
	- delete a local branch
- remote
	- show xxx
		- show info of a remote branch
	- add xxx
		- add a remote repo
- branch
	- list all the branchs
- mv Rename/move files and folder with git history records

  e.g. git mv -k ./a/b ./c/d   option `k` would avoid the "can not move directory into itself" error.

oh-my-zsh

IDE/tools

- Intellij
- vscode

Security