salt Jarvis test.ping
The application configuration for the minion is written in a state file with .sls (salt state file) extension.
The state files should be present inside /srv/salt folder. Create salt folder inside /srv
mkdir –p /srv/salt
In this tutorial am going to create and deploy a simple sate file for installing and starting apache webserver .
You can have the salt file inside the /srv/salt folder. But for good file organization, create a folder named webserver inside the salt folder.
mkdir -p /srv/salt/webserver
Create a apache.sls file inside webserver folder.
vi apache.sls
Copy the following inside the apache.sls file.
Apache-webserver:
pkg.installed:
{% if grains['os'] == 'Ubuntu' %}
- name: apache2
{% endif %}
service.running:
{% if grains['os'] == 'Ubuntu' %}
- name: apache2
{% endif %}
Apache-webserver: It is an user defined name. It can by any name, which serves as a n id.
pkg.installed: This command ensures that the package defined under this command will be installed
{% if grains['os'] == 'Ubuntu' %}
- name: apache2
{% endif %}
Apache package name differs with OS family. So we use python templating to provide appropriate package name using salt grains. Grains is a module which collects the static information about a minion. So , in the above code it checks if the OS is Ubuntu. If yes then apache2 package will be installed. Got redhat system , you have to define grains[‘os’] == ‘redhat’ and the package name will be httpd.
service.running:
{% if grains['os'] == 'Ubuntu' %}
- name: apache2
{% endif %}
Service.running will ensure that the installed service is in running state. The service name is provided to the state using grains os check.
Now, we have a state file, which will install and start apache webserver. Let say , you have to deploy this state to one of minions in your infrastructure. Here is where top file comes in to play. Top.sls file should be present inside /srv/salt folder.
In top.sls file , we define the minions and states. Top file decides which state should be run on a particular minion or on all minions. You can define various environments inside the top file. So that , you can set specific states, which would run only in the specified environments.
Create a top.sls file inside /srv/salt folder. Top.sls for the created apache state is described below.
base:
'jarvis':
- webserver.apache
Base: is the default environment. Normally in base , we would define states that has to be applied on all the minions under the master.
‘jarvis’ is the minion name. If you mention * instead of Jarvis , it will include all the minions under the master.
Webserver.apache is the path to the salt state file. Webserver is the folder inside /srv/salt and apache is the identification for apache.sls file inside webserver folder.
Deploying the state on Minions:
You can deploy the state on a minion from both the master and minion. In other configuration management tools like chef and puppet , you need to configure extra features like mcollective to push a configuration to a node. Push feature in salt comes by default unlike other configuration management tools.
From master:
The following command deploys the state on all minions paralelly as described in the top file.
salt ‘*’ salt.highstate
If you use the minion name instead of * , the state will be deployed on on that particular minion.
salt Jarvis salt.highstate
The following command installs ntp on all the minions without having a state file. You can check if a particular package is installed using this command.
salt '*' state.single pkg.installed name=ntp
From Minion:
Execute the following command to deploy the salt formulas mentioned in the top file from the minion.
salt-call state.highstate
