Install and configure for Ubuntu

This section describes how to install and configure the Messaging service for Ubuntu 14.04 (LTS).

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.


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


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.


      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.
        destination: file
        logAppend: true
        path: /var/log/mongodb/mongod.log
        dbPath: /var/lib/mongo
          enabled: false
        fork: true  # fork and run in background
        pidFilePath: /var/run/mongodb/  # location of pidfile
        port: 27017
        # bindIp:  # Listen to local interface only, comment to listen on all interfaces.
         slowOpThresholdMs: 200
         mode: slowOp
         oplogSizeMB: 2048
         replSetName: catalog


      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.


      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:

      # service mongodb start
    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'))"


      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


      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:

    # apt-get install memcached

    Start memcached service:

    # service memcached start
  2. Install Messaging service and uWSGI:

    # apt-get install python-pip
    # git clone
    # 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.


    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/ with the following content:

    from keystonemiddleware import auth_token
    from zaqar.transport.wsgi import app
    app = auth_token.AuthProtocol(, {})
  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:

    pidfile = /var/run/
    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).


    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/
    # chown ZAQARUSER:ZAQARUSER /var/run/

    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:

    # 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, so disable here
    ;auth_strategy = keystone
    # Modify to make it work with your Identity service.
    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.
    # Messaging service password in Identity service.
    # 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).
    # Token cache time in seconds.
    token_cache_time = TOKEN_CACHE_TIME
    memcached_servers =
    # 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 =
    transport = wsgi
    message_store = mongodb
    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
    # 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
    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
    # 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 an upstart config, it could be named as /etc/init/zaqar.conf:

    description "Zaqar api server"
    author "Your Name <>"
    start on runlevel [2345]
    stop on runlevel [!2345]
    chdir /var/run
    pre-start script
        mkdir -p /var/run/zaqar
        chown zaqar:zaqar /var/run/zaqar
        mkdir -p /var/lock/zaqar
        chown zaqar:root /var/lock/zaqar
    end script
    exec /usr/bin/uwsgi --master --emperor /etc/zaqar/uwsgi

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.


    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.


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.