Install and configure for Red Hat Enterprise Linux and CentOS

This section describes how to install and configure the Messaging service, code-named zaqar for Red Hat Enterprise Linux 7 and CentOS 7.

This section assumes that you already have a working OpenStack environment with at least Identity service installed.

Here you can find instructions and recommended settings for installing Messaging service in small configuration: one web server with Messaging service configured to use replica-set of three MongoDB database servers. Because only one web server is used, the Messaging service installed by using these instructions can’t be considered as high available, see Install and configure.

In this tutorial these server names are used as examples:

  • Web server with Messaging service: WEB0.EXAMPLE-MESSAGES.NET.

  • Database servers: MYDB0.EXAMPLE-MESSAGES.NET, MYDB1.EXAMPLE-MESSAGES.NET, MYDB2.EXAMPLE-MESSAGES.NET.

  • Identity service server: IDENTITY.EXAMPLE-MESSAGES.NET.

Prerequisites

Before you install Messaging service, you must meet the following system requirements:

  • Installed Identity service for user and project management.

  • Python 2.7.

Before you install and configure Messaging, you must create a MongoDB replica-set of three database servers. Also you need to create service credentials and API endpoints in Identity.

  1. Install and configure MongoDB replica-set on database servers:

    1. Install MongoDB on the database servers:

      On each database server follow the official MongoDB installation instructions.

      Note

      Messaging service works with MongoDB versions >= 2.4

    2. Configure MongoDB on the database servers:

      On each database server edit configuration file: /etc/mongod.conf and modify as needed:

      # MongoDB sample configuration for Messaging service.
# (For MongoDB version >= 2.6)
# Edit according to your needs.
systemLog:
  destination: file
  logAppend: true
  path: /var/log/mongodb/mongod.log

storage:
  dbPath: /var/lib/mongo
  journal:
    enabled: false

processManagement:
  fork: true  # fork and run in background
  pidFilePath: /var/run/mongodb/mongod.pid  # location of pidfile

net:
  port: 27017
  # bindIp: 127.0.0.1  # Listen to local interface only, comment to listen on all interfaces.

operationProfiling:
   slowOpThresholdMs: 200
   mode: slowOp

replication:
   oplogSizeMB: 2048
   replSetName: catalog

      Note

      In case of older MongoDB versions (2.4 and 2.5) the configuration file should be written in different format. For information about format for different versions see the official MongoDB configuration reference.

      Warning

      Additional steps are required to secure MongoDB installation. You should modify this configuration for your security requirements. See the official MongoDB security reference.

    3. Start MongoDB on the database servers:

      Start MongoDB service on all database servers:

      # systemctl start mongod

      Make MongoDB service start automatically after reboot:

      # systemctl enable mongod

    4. Configure MongoDB Replica Set on the database servers:

      Once you’ve installed MongoDB on three servers and assuming that the primary MongoDB server hostname is MYDB0.EXAMPLE-MESSAGES.NET, go to MYDB0 and run these commands:

      # mongo local --eval "printjson(rs.initiate())"
# mongo local --eval "printjson(rs.add('MYDB1.EXAMPLE-MESSAGES.NET'))"
# mongo local --eval "printjson(rs.add('MYDB2.EXAMPLE-MESSAGES.NET'))"

      Note

      The database servers must have access to each other and also be accessible from the Messaging service web server. Configure firewalls on all database servers to accept incoming connections to port 27017 from the needed source.

      To check if the replica-set is established see the output of this command:

      # mongo local --eval "printjson(rs.status())"

  2. Source the admin credentials to gain access to admin-only CLI commands:

    $ . admin-openrc

  3. To create the service credentials, complete these steps:

    1. Create the zaqar user:

      $ openstack user create --domain default --password-prompt zaqar
User Password:
Repeat User Password:
+-----------+----------------------------------+
| Field     | Value                            |
+-----------+----------------------------------+
| domain_id | default                          |
| enabled   | True                             |
| id        | 7b0ffc83097148dab6ecbef6ddcc46bf |
| name      | zaqar                            |
+-----------+----------------------------------+

    2. Add the admin role to the zaqar user:

      $ openstack role add --project service --user zaqar admin

      Note

      This command provides no output.

    3. Create the zaqar service entity:

      $ openstack service create --name zaqar --description "Messaging" messaging
+-------------+----------------------------------+
| Field       | Value                            |
+-------------+----------------------------------+
| description | Messaging                        |
| enabled     | True                             |
| id          | b39c22818be5425ba2315dd4b10cd57c |
| name        | zaqar                            |
| type        | messaging                        |
+-------------+----------------------------------+

  4. Create the Messaging service API endpoints:

    $ openstack endpoint create --region RegionOne messaging public http://WEB0.EXAMPLE-MESSAGES.NET:8888
+--------------+---------------------------------------+
| Field        | Value                                 |
+--------------+---------------------------------------+
| enabled      | True                                  |
| id           | aabca78860e74c4db0bcb36167bfe106      |
| interface    | public                                |
| region       | RegionOne                             |
| region_id    | RegionOne                             |
| service_id   | b39c22818be5425ba2315dd4b10cd57c      |
| service_name | zaqar                                 |
| service_type | messaging                             |
| url          | http://WEB0.EXAMPLE-MESSAGES.NET:8888 |
+--------------+---------------------------------------+

$ openstack endpoint create --region RegionOne messaging internal http://WEB0.EXAMPLE-MESSAGES.NET:8888
+--------------+---------------------------------------+
| Field        | Value                                 |
+--------------+---------------------------------------+
| enabled      | True                                  |
| id           | 07f9524613de4fd3905e13a87f81fd3f      |
| interface    | internal                              |
| region       | RegionOne                             |
| region_id    | RegionOne                             |
| service_id   | b39c22818be5425ba2315dd4b10cd57c      |
| service_name | zaqar                                 |
| service_type | messaging                             |
| url          | http://WEB0.EXAMPLE-MESSAGES.NET:8888 |
+--------------+---------------------------------------+

$ openstack endpoint create --region RegionOne messaging admin http://WEB0.EXAMPLE-MESSAGES.NET:8888
+--------------+---------------------------------------+
| Field        | Value                                 |
+--------------+---------------------------------------+
| enabled      | True                                  |
| id           | 686f7b19428f4b5aa1425667dfe4f49d      |
| interface    | admin                                 |
| region       | RegionOne                             |
| region_id    | RegionOne                             |
| service_id   | b39c22818be5425ba2315dd4b10cd57c      |
| service_name | zaqar                                 |
| service_type | messaging                             |
| url          | http://WEB0.EXAMPLE-MESSAGES.NET:8888 |
+--------------+---------------------------------------+

Install and configure Messaging web server

Install and configure memcached, uWSGI and Messaging on the web server WEB0.EXAMPLE-MESSAGES.NET.

  1. Install memcached on web server WEB0.EXAMPLE-MESSAGES.NET in order to cache Identity service tokens and catalog mappings:

    # yum install memcached

    Start memcached service:

    # systemctl start memcached

    Make memcached service start automatically after reboot:

    # systemctl enable memcached

  2. Install Messaging service and uWSGI:

    # yum install python-pip
# git clone https://git.openstack.org/openstack/zaqar.git
# cd zaqar
# pip install . -r ./requirements.txt --upgrade --log /tmp/zaqar-pip.log
# pip install --upgrade pymongo gevent uwsgi

  3. Create Zaqar configiration directory /etc/zaqar/:

    # mkdir /etc/zaqar

  4. Customize the policy file:

    # oslopolicy-sample-generator --config-file etc/zaqar-policy-generator.conf
# cp etc/zaqar.policy.yaml.sample /etc/zaqar/policy.yaml

    Edit any item as needed in policy.yaml.

    Note

    By default, if you do not need custom policy file, you do not need to perform the above steps, then zaqar will use the code’s default policy.

  5. Create log file:

    # touch /var/log/zaqar-server.log
# chown ZAQARUSER:ZAQARUSER /var/log/zaqar-server.log
# chmod 600 /var/log/zaqar-server.log

    Replace ZAQARUSER with the name of the user in system under which the Messaging service will run.

  6. Create /srv/zaqar folder to store uWSGI configuration files:

    # mkdir /srv/zaqar

  7. Create /srv/zaqar/zaqar_uwsgi.py with the following content:

    from keystonemiddleware import auth_token
from zaqar.transport.wsgi import app

app = auth_token.AuthProtocol(app.app, {})

  8. Increase backlog listen limit from default (128):

    # echo "net.core.somaxconn=2048" | sudo tee --append /etc/sysctl.conf

  9. Create /srv/zaqar/uwsgi.ini file with the following content and modify as needed:

    [uwsgi]
https = WEB0.EXAMPLE-MESSAGES.NET:8888,PATH_TO_SERVER_CRT,PATH_TO_SERVER_PRIVATE_KEY
pidfile = /var/run/zaqar.pid
gevent = 2000
gevent-monkey-patch = true
listen = 1024
enable-threads = true
chdir = /srv/zaqar
module = zaqar_uwsgi:app
workers = 4
harakiri = 60
add-header = Connection: close

    Replace PATH_TO_SERVER_CRT with path to the server’s certificate (*.crt) and PATH_TO_SERVER_PRIVATE_KEY with path to the server’s private key (*.key).

    Note

    The uWSGI configuration options above can be modified for different security and performance requirements including load balancing. See the official uWSGI configuration reference.

  10. Create pid file:

    # touch /var/run/zaqar.pid
# chown ZAQARUSER:ZAQARUSER /var/run/zaqar.pid

    Replace ZAQARUSER with the name of the user in system under which the Messaging service will run.

  11. Create Messaging service’s configuration file /etc/zaqar/zaqar.conf with the following content:

    [DEFAULT]
# Show debugging output in logs (sets DEBUG log level output)
#debug = False

# Pooling and admin mode configs
pooling      = True
admin_mode    = True

# Log to file
log_file = /var/log/zaqar-server.log

# This is taken care of in our custom app.py, so disable here
;auth_strategy = keystone

# Modify to make it work with your Identity service.
[keystone_authtoken]
project_domain_name = Default
user_domain_name = Default
project_domain_id = default
project_name = service
user_domain_id = default
# File path to a PEM encoded Certificate Authority to use when verifying
# HTTPs connections. Defaults to system CAs if commented.
cafile = PATH_TO_CA_FILE
# Messaging service user name in Identity service.
username = ZAQARIDENTITYUSER
# Messaging service password in Identity service.
password = ZAQARIDENTITYPASSWORD
# Complete public Identity API endpoint (HTTPS protocol is more preferable
# than HTTP).
www_authenticate_uri = HTTPS://IDENTITY.EXAMPLE-MESSAGES.NET:5000
# Complete admin Identity API endpoint (HTTPS protocol is more preferable
# than HTTP).
identity_uri = HTTPS://IDENTITY.EXAMPLE-MESSAGES.NET:5000
# Token cache time in seconds.
token_cache_time = TOKEN_CACHE_TIME
memcached_servers = 127.0.0.1:11211

[cache]
# Dogpile.cache backend module. It is recommended that Memcache with
# pooling (oslo_cache.memcache_pool) or Redis (dogpile.cache.redis) be
# used in production deployments. Small workloads (single process)
# like devstack can use the dogpile.cache.memory backend. (string
# value)
backend = dogpile.cache.memory
memcache_servers = 127.0.0.1:11211

[drivers]
transport = wsgi
message_store = mongodb
management_store = mongodb

[drivers:management_store:mongodb]
# Mongodb Connection URI. If ssl connection enabled, then ssl_keyfile,
# ssl_certfile, ssl_cert_reqs, ssl_ca_certs options need to be set
# accordingly.
uri = mongodb://MYDB0.EXAMPLE-MESSAGES.NET,MYDB1.EXAMPLE-MESSAGES.NET,MYDB2.EXAMPLE-MESSAGES.NET:27017/?replicaSet=catalog&w=2&readPreference=secondaryPreferred

# Name for the database on mongodb server.
database = zaqarmanagementstore

# Number of databases across which to partition message data, in order
# to reduce writer lock %. DO NOT change this setting after initial
# deployment. It MUST remain static. Also, you should not need a large
# number of partitions to improve performance, esp. if deploying
# MongoDB on SSD storage. (integer value)
partitions = 8

# Uncomment any options below if needed.

# Maximum number of times to retry a failed operation. Currently
# only used for retrying a message post.
;max_attempts = 1000

# Maximum sleep interval between retries (actual sleep time
# increases linearly according to number of attempts performed).
;max_retry_sleep = 0.1

# Maximum jitter interval, to be added to the sleep interval, in
# order to decrease probability that parallel requests will retry
# at the same instant.
;max_retry_jitter = 0.005

# Frequency of message garbage collections, in seconds
;gc_interval = 5 * 60

# Threshold of number of expired messages to reach in a given
# queue, before performing the GC. Useful for reducing frequent
# locks on the DB for non-busy queues, or for worker queues
# which process jobs quickly enough to keep the number of in-
# flight messages low.
#
# Note: The higher this number, the larger the memory-mapped DB
# files will be.
;gc_threshold = 1000

[drivers:message_store:mongodb]
# This section has same set of available options as
# "[drivers:management_store:mongodb]" section.
#
# If pooling is enabled, all pools inherit values from options in these
# settings unless overridden in pool creation request. Also "uri" option
# value isn't used in case of pooling.
#
# If ssl connection enabled, then ssl_keyfile, ssl_certfile, ssl_cert_reqs,
# ssl_ca_certs options need to be set accordingly.

# Name for the database on MondoDB server.
database = zaqarmessagestore

[transport]
max_queues_per_page = 1000
max_queue_metadata = 262144
max_mesages_per_page = 10
max_messages_post_size = 262144
max_message_ttl = 1209600
max_claim_ttl = 43200
max_claim_grace = 43200

[signed_url]
# Secret key used to encrypt pre-signed URLs. (string value)
secret_key = SOMELONGSECRETKEY

    Edit any options as needed, especially the options with capitalized values.

  12. Create a service file for Messaging service /etc/systemd/system/zaqar.uwsgi.service:

    [Unit]
Description=uWSGI Zaqar
After=syslog.target

[Service]
ExecStart=/usr/bin/uwsgi --ini /srv/zaqar/uwsgi.ini
# Requires systemd version 211 or newer
RuntimeDirectory=uwsgi
Restart=always
KillSignal=SIGQUIT
Type=notify
StandardError=syslog
NotifyAccess=all
User=ZAQARUSER
Group=ZAQARUSER

[Install]
WantedBy=multi-user.target

    Replace ZAQARUSER with the name of the user in system under which the Messaging service will run.

Finalize installation

Now after you have configured the web server and the database servers to have a functional Messaging service, you need to start the service, make the service automatically start with the system and define the created MongoDB replica-set as Messaging’s pool.

  1. Start Messaging service on the web server:

    # systemctl start zaqar.uwsgi.service

  2. Make Messaging service start automatically after reboot on the web server:

    # systemctl enable zaqar.uwsgi.service

  3. Configure pool:

    # curl -i -X PUT https://WEB0.EXAMPLE-MESSAGES.NET:8888/v2/pools/POOL1 \
           -d '{"weight": 100, "uri": "mongodb://MYDB0.EXAMPLE-MESSAGES.NET,MYDB1.EXAMPLE-MESSAGES.NET,MYDB2.EXAMPLE-MESSAGES.NET:27017/?replicaSet=catalog&w=2&readPreference=secondaryPreferred", "options": {"partitions": 8}}' \
           -H "Client-ID: CLIENT_ID" \
           -H "X-Auth-Token: TOKEN" \
           -H "Content-type: application/json" \

    Replace POOL1 variable with the desired name of a pool.

    Replace CLIENT_ID variable with the universally unique identifier (UUID) which can be generated by, for example, uuidgen utility.

    Replace TOKEN variable with the authentication token retrieved from Identity service. If you choose not to enable Keystone authentication you won’t have to pass a token.

    Note

    The options key in curl request above overrides any options (specified in configuration file or default) in [drivers:message_store:mongodb] Messaging service configuration file’s section.

Tip

In larger deployments, there should be many load balanced web servers. Also the management store databases and the message store databases (pools) should be on different MongoDB replica-sets.