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Continuous deployment with Jenkins and Salt

LinuxCon CloudOpen ContainerCon

North America 2015, Seattle

Anirban Saha

About me

Techie…

Traveller…

Thinker…

Author of ‘Salt Cookbook’

Deployment

Should be…

• Simple

• Stable

• Fast (good to have…)

• Reliable

• One click

Problems faced

• Code distribution

• Additional tasks (commands, migrations)

• Latency

• Parallel execution

• Batch deployments

• Ensuring uptime

Methods availableDeployment

Configuration management tools :

• Puppet, Chef, Ansible, Salt

Remote execution tools:

• SSH, Parallel SSH, Rundeck

Packages:

• Code packaged as RPM or DEB files

Code storage

• GIT server (Github, Gitlab, Bitbucket, etc.)

• Object storage (Amazon S3, Swift, etc.)

• Package repositories (YUM/Debian)

• Configuration management repositories

• File servers managed manually

ProblemsDeployment:

• Remote execution tools :

• Time consuming (over SSH)

• Need to maintain inventory of hosts

Code storage:

• GIT repositories:

• Usually centrally located, latency when deployed from GIT

• Package repositories (RPM/DEB):

• Problems in simultaneously updating repo metadata

Rollback:

• Version manipulation is a problem with most configuration

management and remote execution tools

Salt

Provides…

• Agent based communication

• Fast execution

• Orchestration

• Batch execution

• Strong Integration with providers and

services

Salt featuresTargeting deployment nodes :

• By hostname

• ‘myappweb*’

• By specific grains

• -G ‘node_type:webserver’

• By nodegroups

• -N webgroup

Salt featuresTask dependencies :

• Salt requisites to make tasks dependent on each other

get_archive:

module.run:

.

.

deploy_app:

module.run:

.

.

- require:

- module: get_archive

Salt featuresOrchestration :

webgrp2_deploy: salt.state:

- tgt: ' webgrp2' - tgt_type: nodegroup - sls:

- webserver.deploy - require:

- salt: webgrp1_deploy

webgrp1_deploy: salt.state:

- tgt: 'webgrp1'- tgt_type: nodegroup - sls:

- webserver.deploy

Salt features

Batch Execution :

• By number of hosts

• --batch-size 5

• Executes on 5 hosts at a time

• By percentage of hosts

• --batch-size 25%

• Executes on 25% of total target

hosts at a time

Salt features

Salt API:

# curl -H "Accept: application/json"

-d secretkey= "mysupersecretkey"

-k https://10.0.0.2:8080/hook/deploy

{"success": true}

Tools

To be used…

• GIT for code repository

• Jenkins for CI

• Ant for build and tasks

• Amazon S3 for code archive storage

• Salt for deployment

• Shell scripts (good old bash) for

additional tasks

Salt deployment methods

• Salt hosted on the Jenkins server.

Jenkins calls Salt binary

• Salt hosted independently.

Jenkins calls Salt via SSH

• Jenkins calls Salt via Salt API

Objective

Steps• salt-cloud used to launch instances

• Post install actions used to synchronize EC2 grains

• Salt reactor used to run states on new instances ,

perform deployment and register with load balancer

• Jenkins build job used to build new code, create tags

and push new deployment ready archive to Amazon

S3

• Jenkins deploy job used to fetch new code version

and deploy code on target servers

Steps explained• Salt cloud is used to spawn instances

• Following parameter is provided in the profile to push custom EC2 grains,

• sync_after_install: grains

• The node is registered and deregistered from the load balancer with the

following module definition,

register:

module.run:

- name: boto_elb.register_instances

- m_name: mywebapp

- instances:

- {{ grains['ec2']['instance_id'] }}

• Here ['ec2']['instance_id'] is one of the custom grains pushed to the node

Steps explained

Fetching archive:

Salt s3 execution module used to get code archive from

Amazon S3

fetch_app_archive: module.run:

- name: s3.get

- bucket: mywebapp-us

- path: mywebapp-{{ app_version }}.tar

- local_file: /tmp/mywebapp-{{ app_version }}.tar

Steps explained

Setting App version grain:

After every deploy, a grain is set to record the

app version deployed for tracking,

app_version:

grains.present:

- value: {{ app_version }}

- require:

- cmd: deploy_app

Steps explainedDeployment based on App version:

At every deploy, it is checked if the version to

be deployed is already on the node using the

app_version grain,

{% if grains['app_version'] != app_version %}

deregister:

fetch_app_archive:

deploy_app:

register:

{% endif %}

Lets do it then !!!

Demo repository

Get the demo repository at the

following location,

https://github.com/rosesnthornz/

cloudopen-na-2015

Questions ?

Contact

Email :

sahaanirban1988@gmail.com

Twitter : @rosesnthornz

Thank You !!!