tpaexec provision
=================

Provision creates instances and other resources required by the cluster.

The exact details of this process depend both on the architecture
(e.g.  :ref:`M1 <M1>`  ) and platform (e.g.  :ref:`Using awscli to change volume attributes <Using awscli to change volume attributes>`  ) that you
selected while configuring the cluster.

At the end of the provisioning stage, you will have the required number
of instances with the basic operating system installed, which TPA can
access via ssh (with sudo to root).

Prerequisites
-------------

Before you can provision a cluster, you must generate the cluster
configuration with :ref:`tpaexec configure <Cluster configuration>` 

(and edit config.yml to fine-tune the configuration if needed).

You may need additional platform-dependent steps. For example, you need
to obtain an AWS API access keypair to provision EC2 instances, or set
up LXD or Docker to provision containers. Consult the platform
documentation for details.

Quickstart
----------

.. code:: bash

   [tpa]$ tpaexec provision ~/clusters/speedy

   PLAY [Provision cluster] **********************************************************
   ...

   TASK [Set up EC2 instances] *******************************************************
   changed: [localhost] => (item=us-east-1:quirk)
   changed: [localhost] => (item=us-east-1:keeper)
   changed: [localhost] => (item=us-east-1:zealot)
   changed: [localhost] => (item=us-east-1:quaver)
   changed: [localhost] => (item=us-east-1:quavery)
   ...

   TASK [Generate ssh_config file for the cluster] ***********************************
   changed: [localhost]

   PLAY RECAP ************************************************************************
   localhost                  : ok=128  changed=20   unreachable=0    failed=0   

   real    2m19.386s
   user    0m51.819s
   sys     0m27.852s

This command will produce lots of output (append ``-v`` , ``-vv`` , etc.
to the command if you want even more verbose output). The output is also
logged to ``ansible.log`` in the cluster directory. This can be
overriden by setting the environment variable ``ANSIBLE_LOG_PATH`` to
the path and name of the desired logfile.

If it completes without error, you may proceed to run :ref:`tpaexec deploy <tpaexec deploy>`  to
install and configure software.

Options
-------

When provisioning cloud instances, it is especially important to make
sure instances are directly traceable to a human responsible for them.
By default, TPA will tag EC2 instances as being owned by the login name
of the user running ``tpaexec provision`` .

Specify ``--owner <name>`` to change the name (e.g., if your username
happens to be something generic, like postgres or ec2-user). You may use
initials, or “Firstname Lastname”, or anything else to uniquely identify
a person.

Any other options you specify are passed on to Ansible.

Accessing the instances
-----------------------

After provisioning completes, you should be able to SSH to the instances
(after a brief delay to allow the instances to boot up and install their
SSH host keys). As shown in the output above, tpaexec will generate an
ssh_config file for you to use.

.. code:: bash

   [tpa]$ cd ~/clusters/speedy
   [tpa]$ cat ssh_config
   Host *
       Port 22
       IdentitiesOnly yes
       IdentityFile "id_speedy"
       UserKnownHostsFile "known_hosts tpa_known_hosts"
       ServerAliveInterval 60

   Host quirk
       User admin
       HostName 54.227.207.189
   Host keeper
       User admin
       HostName 34.229.111.196
   Host zealot
       User admin
       HostName 18.207.108.211
   Host quaver
       User admin
       HostName 54.236.36.251
   Host quavery
       User admin
       HostName 34.200.214.150
   [tpa]$ ssh -F ssh_config quirk
   Linux quirk 4.9.0-6-amd64 #1 SMP Debian 4.9.82-1+deb9u3 (2018-03-02) x86_64

   The programs included with the Debian GNU/Linux system are free software;
   the exact distribution terms for each program are described in the
   individual files in /usr/share/doc/*/copyright.

   Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
   permitted by applicable law.
   Last login: Sat Aug  4 12:31:28 2018 from 136.243.148.74
   admin@quirk:~$ sudo -i
   root@quirk:~# 

You can run :ref:`tpaexec deploy <tpaexec deploy>`  immediately after provisioning. It will wait
as long as required for the instances to come up. You do not need to
wait for the instances to come up, or ssh in to them before you start
deployment.

Generated files
---------------

During the provisioning process, a number of new files will be created
in the cluster directory:

.. code:: bash

   [tpa]$ ls ~/clusters/speedy
   total 240
   - rw-r--r-- 1 ams ams 193098 Aug  4 17:59 ansible.log
   drwxr-xr-x 2 ams ams   4096 Aug  4 17:38 commands
   - rw-r--r-- 1 ams ams   1442 Aug  4 17:54 config.yml
   lrwxrwxrwx 1 ams ams     51 Aug  4 17:38 deploy.yml -> 
                                /opt/EDB/TPA/architectures/M1/deploy.yml
   drwxr-xr-x 2 ams ams   4096 Aug  4 17:38 hostkeys
   - rw------- 1 ams ams   1675 Aug  4 17:38 id_speedy
   - rw------- 1 ams ams   1438 Aug  4 17:38 id_speedy.ppk
   - rw-r--r-- 1 ams ams    393 Aug  4 17:38 id_speedy.pub
   drwxr-xr-x 4 ams ams   4096 Aug  4 17:50 inventory
   - rw-r--r-- 1 ams ams   2928 Aug  4 17:50 tpa_known_hosts
   - rw-r--r-- 1 ams ams    410 Aug  4 17:50 ssh_config
   - rw-r--r-- 1 ams ams   3395 Aug  4 17:59 vars.json
   drwxr-xr-x 2 ams ams   4096 Aug  4 17:38 vault

We’ve already studied the ssh\ *config file, which refers to the
\`id*\ \*\ ``files (an SSH keypair generated for the cluster) and``\ tpa_known_hosts\ ``(the signatures of the``\ hostkeys/\`
installed on the instances).

The ``vars.json`` file may be used by ``tpaexec provision`` on
subsequent invocations with ``--cached`` .

The ``inventory/`` directory contains static and dynamic inventory files
as well as group and host variable definitions from config.yml.

.. code:: bash

   [tpa]$ cat inventory/00-speedy
   [tag_Cluster_speedy]
   quirk ansible_host=54.227.207.189 node=1 platform=aws
   keeper ansible_host=34.229.111.196 node=2 platform=aws
   zealot ansible_host=18.207.108.211 node=3 platform=aws
   quaver ansible_host=54.236.36.251 node=4 platform=aws
   quavery ansible_host=34.200.214.150 node=5 platform=aws

   [tpa]$ cat inventory/group_vars/tag_Cluster_speedy/01-speedy.yml 
   cluster_name: speedy
   cluster_tag: tag_Cluster_speedy
   postgres_version: 15
   tpa_version: v23.10-22-g30c1d5ea
   tpa_2q_repositories: []
   vpn_network: 192.168.33.0/24

   [tpa]$ cat inventory/host_vars/zealot/02-topology.yml
   role:

   - barman

   - log-server

   - openvpn-server

   - monitoring-server

   - witness
   upstream: quirk

If you now change a variable in config.yml and rerun provision, these
files will be updated. If you don’t change the configuration, it won’t
do anything. If you add a new instance in config.yml and rerun, it will
bring up the new instance without affecting the existing ones.
