OpenStack is a collection of services, with each service running on at least one server(node)
cumulus@server01:~$ openstack service list
+----------------------------------+-----------+--------
---+
| ID                               | Name      | Type
   |
+----------------------------------+-----------+--------
---+
| 0e4cbb5c4c1046a7a89e2578cb011a6e | neutron   | network   |
| 37b351b5be1842758fc98f65aba11a29 | nova      | compute   |
| 3e0b056517334fbc8794ef7ec6a7a4c7 | glance    | image   |
| 86849f24e69143d8aa41007ea81e3a8c | keystone  | identity  |
| ae795f1be3bb48bc865e219f4f2ecc35 | placement | placement |
+----------------------------------+-----------+--------
---+
This OpenStack deployment only has few services, but depending on the need, it can be installed with various other optional services such as Cinder, Heat, Swift, etc.
Keystone is the identity service used to authenticate any communication or requests among services or between users and services
By default, there will be a 'service' project, in the 'default' domain, that contains user accounts for each OpenStack service except keystone, since we have 4 services excluding keystone, we also should have 4 respective users in the 'service' project
cumulus@server01:~$ openstack project list --domain default
+----------------------------------+---------+
| ID                               | Name    |
+----------------------------------+---------+
| 3c119483a4704451bd24ccaa98121901 | admin   |
| 5b2668bd4dfe4bdf9ff98ce794462140 | service |
| 768939cc621f43728ff90332dee58e95 | demo    |
+----------------------------------+---------+
cumulus@server01:~$ openstack user list --project service
+----------------------------------+-----------+
| ID                               | Name      |
+----------------------------------+-----------+
| fe656dc2c15541c1ab96f6fdc1df39f4 | nova      |
| e9ec70ddc0114ed1a1fa97bdf007c200 | glance    |
| c30b5df613ae4e818c8f7b38afdc2dae | neutron   |
| bf8e72b9dab54fce9582d0eb6acee95a | placement |
+----------------------------------+-----------+
Each service would have 3 endpoint URLs - admin, public, and private associated with specific ports on the controller node
cumulus@server01:~$ openstack endpoint list
+----------------------------------+-----------+--------
------+--------------+---------+-----------+------------
-----------------+
| ID                               | Region    | Service
Name | Service Type | Enabled | Interface | URL
                 |
+----------------------------------+-----------+--------
------+--------------+---------+-----------+------------
-----------------+
| 10c2d133795445f2b47b21e50e6c2660 | RegionOne | placeme
nt    | placement    | True    | admin     | http://cont
roller:8778      |
| 1d46eb4d520b403eb3cd109887a541af | RegionOne | keyston
e     | identity     | True    | public    | http://cont
roller:5000/v3   |
| 2e029d3a71e84e12a10c1da8321f3ad0 | RegionOne | placeme
nt    | placement    | True    | public    | http://cont
roller:8778      |
| 50e2205ffba8488d9514a3d509e796e2 | RegionOne | keyston
e     | identity     | True    | internal  | http://cont
roller:5000/v3   |
| 539c26f035d744208bdaa07f566f9d1c | RegionOne | glance
      | image        | True    | public    | http://cont
roller:9292      |
| 6cdd49a594e1481d968332c38e1a96b3 | RegionOne | nova
      | compute      | True    | admin     | http://cont
roller:8774/v2.1 |
| 73df359bd6414703869bcb7e6a48bac5 | RegionOne | neutron
      | network      | True    | internal  | http://cont
roller:9696      |
| 7c1345979e434c4fbe8c8d0dd5ef4b73 | RegionOne | nova
      | compute      | True    | internal  | http://cont
roller:8774/v2.1 |
| 7fc148d9e6054e26a0a3b8e4a2b83858 | RegionOne | glance
      | image        | True    | admin     | http://cont
roller:9292      |
| 8b269c78f6394ce795a5206159735e54 | RegionOne | neutron
| 7fc148d9e6054e26a0a3b8e4a2b83858 | RegionOne | glance
      | image        | True    | admin     | http://cont
roller:9292      |
| 8b269c78f6394ce795a5206159735e54 | RegionOne | neutron
      | network      | True    | public    | http://cont
roller:9696      |
| ac68952f118047449136cdc60c64bdf5 | RegionOne | glance
      | image        | True    | internal  | http://cont
roller:9292      |
| bc58782a043c40aeae8b89efbb17f2d4 | RegionOne | keyston
e     | identity     | True    | admin     | http://cont
roller:35357/v3  |
| d713f751883d42199c5619281c759a83 | RegionOne | neutron
      | network      | True    | admin     | http://cont
roller:9696      |
| e693a9c0cea74ff69e2e4544353f9e48 | RegionOne | placeme
nt    | placement    | True    | internal  | http://cont
roller:8778      |
| e6ce0a72d6a643c3a321921b811504ff | RegionOne | nova
      | compute      | True    | public    | http://cont
roller:8774/v2.1 |
+----------------------------------+-----------+--------
------+--------------+---------+-----------+------------
-----------------+
Few service types, also provide an option check their APIs status.
To view the APIs/components status of the compute service (nova).
cumulus@server01:~$ openstack compute service list
+----+------------------+----------+----------+---------
+-------+----------------------------+
| ID | Binary           | Host     | Zone     | Status
| State | Updated At                 |
+----+------------------+----------+----------+---------
+-------+----------------------------+
|  1 | nova-scheduler   | server01 | internal | enabled
| up    | 2018-06-23T03:32:59.000000 |
|  2 | nova-consoleauth | server01 | internal | enabled
| up    | 2018-06-23T03:33:01.000000 |
|  3 | nova-conductor   | server01 | internal | enabled
| up    | 2018-06-23T03:33:01.000000 |
|  8 | nova-compute     | server04 | nova     | enabled
| up    | 2018-06-23T03:32:55.000000 |
|  9 | nova-compute     | server03 | nova     | enabled
| up    | 2018-06-23T03:32:59.000000 |
| 10 | nova-compute     | server02 | nova     | enabled
| up    | 2018-06-23T03:33:00.000000 |
+----+------------------+----------+----------+---------
+-------+----------------------------+
To view the APIs/components status of the network service (neutron)
cumulus@server01:~$ openstack network agent list
+--------------------------------------+----------------
----+----------+-------------------+-------+-------+----
-----------------------+
| ID                                   | Agent Type
    | Host     | Availability Zone | Alive | State | Bin
ary                    |
+--------------------------------------+----------------
----+----------+-------------------+-------+-------+----
-----------------------+
| 089aae65-05ee-4961-8f51-ed57ce025488 | L3 agent
    | server01 | nova              | XXX   | UP    | neu
tron-l3-agent          |
| 1f1a00a3-8ac3-4684-9b37-0b20966ed024 | Metadata agent
    | server01 | None              | XXX   | UP    | neu
tron-metadata-agent    |
| 2df25daa-b968-42d7-907f-39c26137798c | Metadata agent
    | server03 | None              | :-)   | UP    | neu
tron-metadata-agent    |
| 3a371a7d-d48a-4940-af94-8d84235bba04 | Metadata agent
    | server04 | None              | :-)   | UP    | neu
tron-metadata-agent    |
| 7e2cf6e2-d15b-429d-9503-17c0d5f8764a | DHCP agent
    | server01 | nova              | XXX   | UP    | neu
tron-dhcp-agent        |
| b0e89fee-488a-4c9c-9d2f-624b657f5a72 | Linux bridge ag
ent | server02 | None              | :-)   | UP    | neu
tron-linuxbridge-agent |
| b2947866-f55f-4a63-a9d5-94d18d8753f5 | Linux bridge ag
ent | server03 | None              | :-)   | UP    | neu
tron-linuxbridge-agent |
| c8648f2f-dd7b-47b3-8e56-193e411a40a7 | Linux bridge ag
ent | server04 | None              | :-)   | UP    | neu
tron-linuxbridge-agent |
| e7f6c113-0b01-4561-96ec-c05dc25381a1 | Linux bridge ag
ent | server01 | None              | :-)   | UP    | neu
tron-linuxbridge-agent |
| f93ae7f4-ebdd-499d-84fa-2edc1e194820 | Metadata agent
    | server02 | None              | :-)   | UP    | neu
tron-metadata-agent    |
+--------------------------------------+----------------
----+----------+-------------------+-------+-------+----
-----------------------+
There would be databases in mysql, for all the OpenStack services
cumulus@server01:~$ sudo mysql -h localhost
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 31
Server version: 5.7.22-0ubuntu0.16.04.1 (Ubuntu)
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| glance             |
| keystone           |
| mysql              |
| neutron            |
| nova               |
| nova_api           |
| nova_cell0         |
| performance_schema |
| sys                |
+--------------------+
10 rows in set (0.01 sec)
mysql> exit
Bye
--end-of-post--