Tuesday, April 28, 2020

Moving from NGINX OSS to NGINX Plus - part 3

In the previous blog posts I have been working with NGINX OSS (aka open source).
There is a lot you can do with the open source version, and using Ansible to drive it, you can automate most thinks that you want.

If you are coming in mid-stream, there are some assumptions in this demo.  Go back to the provisioning in AWS blog if you want the full detail.
The assumptions: local file system inventory files, Ansible host deployed to the same VPC as the remote machines, variable files, run the playbooks from the same folder as the inventory and variable files.

Starting here, I am going to focus on NGINX Plus.
It is the paid version of NGINX and includes extra features beyond what the open source version does.
A little bit of search will give you feature comparisons such as: https://www.nginx.com/products/nginx/#compare-versions

The reason that I am going to start talking about NGINX Plus is dynamic modules.

Moving from OSS to Plus

Moving from OSS to Plus can be done a couple different ways.
One way is to simply spin up new machine instances with NGINX Plus installed and point the traffic over and you are done.
In this example I am going to re-use the same loadbalancer machine that I setup in AWS and have NGINX OSS installed on to.

I am not concerned with downtime in this demo (not that it isn't just minutes) so I am going to uninstall OSS and re-install with the Plus binaries.

ansible-playbook nginx-remove.yaml -i loadbalancers

You can find this playbook here: https://github.com/brianehlert/ansible-nginx-examples/blob/master/nginx_remove.yaml
It literally stops and removes NGINX.  No frills, no fancy.  Nothing to see here, move along.

Installing NGINX Plus

NGINX Plus is delivered from NGINX and you need a subscription to access it.

Using the Ansible Role for NGINX, it isn't very different from NGINX OSS.
The playbook here: https://github.com/brianehlert/ansible-nginx-examples/blob/master/nginx_lb_plus.yaml
looks nearly identical to the playbook for installing NGINX OSS.  The key differences arevthe variables file and the workflow that happens under the hood.

At the top of the variables file: https://github.com/brianehlert/ansible-nginx-examples/blob/master/nginx_lb_plus_vars.yaml
There are additional settings of:
nginx_type: plus - install the plus version of NGINX
nginx_delete_license: true - delete the Plus repository license from the remote (good to do)
nginx_license: this is your license for access the NGINX Plus repository stored in the playbook directory.
nginx_rest_api_*: these relate to enabling the nginx plus api, which you probably want.

After that, the template variables begin as they were for NGINX OSS.
What happens
Just like with the playbook for NGINX OSS, the vars file nginx_lb_plus_vars.yaml variable file is read in the variables webserver1 and webserver2 are replaced with the values from the webservers inventory file.

Once done

You should be all set with a functioning load balancer again.  This time with NGINX Plus instead of NGINX OSS.

The next step, lets add and configure a module.

Pre_ and Post_tasks

This is the first time I have used pre_tasks and post_tasks.
These are useful when your playbook invokes one Role.
The pre_tasks are executed before the Role(s) and the post_tasks are executed after.

While you can use these when multiple roles are listed with include_role, you do have to be careful that the pre and post tasks align with all the Roles being invoked by the playbook.

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