Installing Aquilon

Authors
Luis Fernando Muñoz Mejías, Michel Jouvin

The instruction below describes how to install Aquilon from the sources and run it as a non-root user. Some of the installation steps described here require that you can become root on the machine. The configuration of a site with Aquilon is covered in a specific page.

Note: the commands provided in this documentation are intended to be copy/pasted.

Install Required Packages

There are two set of packages required by Aquilon: the base OS packages and the Python dependencies. For the latter, you have the choice between using RPM to install them or using the Python pip command, preferably in a Python Virtual Environment. Both methods should work but pip is probably the easiest way to use the last version for all dependencies as the RPMs are not always in sync with them.

Before starting with the package installation, you should ensure you have the following YUM repositories configured on your machine:

Mandatory RPM Packages

Aquilon requires an EL7 system with at least the following RPMs installed. Use the yum command below to check it they are installed and install the missing ones:

yum install ant-apache-regexp ant-contrib \
  gcc git git-daemon java-1.8.0-openjdk-devel libxslt libxml2 make panc \
  knc krb5-workstation \
  protobuf-compiler protobuf-devel \
  python-devel python-setuptools \
  aii-server

Note: up to Quattor 18.6.0 included, aii-server has a missing requirement for its dependency perl-IPC-Run that must be added explicitly to the yum command.

Also install a web server. Depending on your preferences, you can use:

  • Apache:

      yum install httpd
    
  • Nginx:

      yum install nginx
    

You also need the following packages for Kerberos, depending on your Kerberos infrastructure:

  • If you don’t use an external Kerberos server, you need to install the server package:

      yum install krb5-server
    
  • If you rely on Microsoft Active Directory:

      yum install msktutil
    

In addition, you need the package appropriate for the database back-end that you choose. There are 2 options:

  • SQLite: this is the easiest choice, as there is no configuration involved, if you want to build quickly an Aquilon configuration for testing purposes but it is not recommended for a production installation, especially a large one. In addition to the scalability limits, SQLite as no incremental backup features and only a limited support for database upgrades (not all the features Aquilon rely on for these upgrades, in particular for defining constraints, are available). To use SQLite, you need the following package:

      yum install sqlite
    
  • PostgreSQL: this is a real database service, recommended for a production installation. It offers many advanced administration features, including continuous backup. It requires an additional step to configure the server, documented below. The required packages are:

      yum install postgres-devel postgres-server postgres-contrib
    

Note: this is (almost) impossible to change the configuration back-end of an existing database as there is no easy way to dump the database with one back-end and import it in another back-end. Changing the back-end basically involves rebuilding the site configuration from scratch.

If using a distribution other than EL7, you will need python 2.7.x (with virtualenv support installed) and git 1.7+.

Using RPM

The first option to install the Aquilon Python dependencies is to use the rpm command. In this case, you need to be root to install Aquilon.

RPMs to install are:

yum install python-dateutil python-lxml python-psycopg2 \
  python-coverage python-ipaddr python-mako python-jsonschema \
  PyYAML python-cdb python-twisted-runner python-twisted-web \
  protobuf-python python-pip

In addition install the sqlalchemy module from PyPI (the EPEL version is too old):

pip install sqlalchemy

Using a Python Virtual Environment

The alternative to installing Python dependencies RPMs is to build a Python VirtualEnv. One advantage is rely on the PyPi repository which contains the most recent version of all Python modules. It is also not required to be root (but this is necessary for several other steps described here).

The main steps involved in the creation of the VirtualEnv are:

  • Ensure that your system has the following packages installed or install them if it is not the case (the packages are required only during the installation process):
    • gcc
    • libxslt-devel (and its dependencies)
    • libyaml-devel
    • PostgreSQL-devel
    • python-virtualenv
  • Create the Python Virtual Environment and activate it. In this documentation, we assume that the Virtual Environment is created in /var/quattor/aquilon-venv directory but you can adapt the instructions in this documentation to the directory you actually want to use:

      virtualenv --prompt="(aquilon) " /var/quattor/aquilon-venv
      . /var/quattor/aquilon-venv/bin/activate
    
  • Ensure that you have the latest setuptools:

      pip install --upgrade setuptools
    
  • Install Python dependencies with the pip command:

      pip install coverage
      pip install functools32
      pip install ipaddress
      pip install lxml
      pip install mako
      pip install jsonschema
      pip install psycopg2
      pip install protobuf
      pip install python-cdb
      pip install python-dateutil
      pip install pyyaml
      pip install sqlalchemy
      pip install twisted
      pip install virtualenv
    

Configuring Database

This step applies only for installation using Postgres as their database back-end (recommended, see above). After installing the RPMs, it is necessary to initialise the Postgres environment and to create a database for Aquilon. The main steps are:

  • Initialising the Postgres environment:
/usr/bin/PostgreSQL-setup
  • Create a Postgres account for Aquilon. This must match the Linux user that will be used by the broker, typically aquilon:
su - postgres -c 'createuser aquilon'
  • Create the Aquilon database and define the account created previously as its owner:
su - postgres -c 'createdb -O aquilon aquilon'
  • Enable and start the PostgreSQL service:
systemctl enable PostgreSQL
systemctl start PostgreSQL

Building Aquilon protocols

You need to build the Aquilon protocols Python module from sources with the following commands (if using a VirtualEnv, be sure that it is activated or the Aquilon protocols will get installed at the wrong place):

cd your_work_directory
git clone https://github.com/quattor/aquilon-protocols.git
cd aquilon-protocols
./setup.py install

If you want the Python module to be installed in a location other than the default one for your Python installation, add --prefix or --install-base option. The files other than the Python modules are not really needed to run Aquilon.

Installing Aquilon

To install Aquilon, clone its source repository. The following command will install Aquilon in /opt/aquilon.

cd /opt/
git clone https://github.com/quattor/aquilon.git

It is possible to install Aquilon in another location: in this case, you must define /opt/aquilon as a symlink to the directory containing the Aquilon repository.

Installation Test

If the installation is done as root and all the dependencies (listed in /opt/aquilon/setup.py) have been installed as RPM or using the pip command, there are no more installation steps to do and you should be able to run the /opt/aquilon/tests/dev_aqd.sh. This command should fail with:

sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) unable to open database file

Any other error means that something is wrong in the installation

Broker Configuration

Create the Broker Configuration

The Aquilon broker configuration file is /etc/aqd.conf. A configuration template is distributed with Aquilon, /opt/aquilon/etc/aqd.conf.noms, and should work as is if you use the standard directory layout for Aquilon and its data and a SQLite database:

  • /opt/aquilon: Aquilon code
  • /var/quattor: parent directory for all the Aquilon data directories (database, log files, templates…)

All the possible configuration options can be found in /opt/aquilon/etc/aqd.conf.defaults. To change a default, define the corresponding setting in /etc/aqd.conf (but don’t modify /opt/aquilon/etc/aqd.conf.defaults). The main configuration options that you may want to change are:

  • Database
    • SQLite: this is the default database back-end, use dbfile in [database_sqlite] to specify a non standard database file by adding the following in /etc/aqd.conf:

      [database_sqlite]
      dbfile = /path/to/your/aquilon.db
      
    • Postgres: change the database back-end and define the database name by adding the following sections to /etc/aqd.conf:

      [database]
      database_section = database_PostgreSQL
      
      [database_PostgreSQL]
      dbname = aquilon
      
  • Directories for Aquilon data directories: logdir, rundir
  • Pan compiler location: pan_compiler. It must be the path of panc jar file.
  • Installation path of Aquilon protocols: directory in protocolssection. It must reflect the installation path used previously, at the installation of the protocols. This is typically /var/quattor/aquilon-venv/lib/python2.7/site-packages if a VirtualEnv is used or /usr/lib/python2.7/site-packages otherwise.

When defining paths, you can use variables defined in the [DEFAULT] section with the following syntax:

%(variable)s

The default configuration defines 2 such variables:

  • basedir: Aquilon installation path (/opt/aquilon)
  • quattordir: Aquilon data parent directory (var/quattor)

You can define other variables if convenient for your site and use them around the configuration.

Configure the Kerberos Server

If you don’t rely on an existing Kerberos server, you need to set up one. See the following instructions. In /etc/krb5.conf, change server to servername in [realms] section.*

Note: if you install the Kerberos on a new machine with not a lot of activity, it may take a while for the Kerberos database creation to complete, due to its need to wait for enough randomness entropy. To speed up this process, you can follow the recipe in the following blog post.

Be sure to define properly the domain associated with your realm: it must match your actual domain.

If you don’t run as root, be sure to create a keytab for the current user.

Create a User to Run the Broker

It is recommended not to run the broker as root. This cause quite a number of problem with Kerberos in particular. This documentation assumes that the user is called aquilon and it is recommended to keep this name.

First create a user with the adduser command, if you don’t use a specific tool for this purpose:

adduser aquilon
mkdir /var/spool/keytabs
chown aquilon:aquilon /var/spool/keytabs

Then you need to create a Kerberos principal that will be used by the broker and create a keytab that will be readable by the broker account. How to do this depends on the Kerberos implementation used.

MIT Kerberos

If you use a standalone Kerberos instance, use the kadmin.local command. If you have a central Kerberos infrastructure (the server is not on the Aquilon broker machine), use kadmin instead.

bash> kadmin.local
kadmin.local: addprinc aquilon
kadmin.local: addprinc aquilon/your.host.fqdn
kadmin.local: ktadd -k /var/spool/keytabs/aquilon
kadmin.local: quit
bash> chown aquilon:aquilon /var/spool/keytabs/aquilon

The created principal can be used to execute aq commends, in particular to give admin rights to other principal with aq permission.

Microsoft Active Directory

If you use Microsoft Active Directory as your Kerberos infrastructure, you need to use the msktutil tool.

  • Create an Active Directory user that will be used by the broker, using the standard Active Directory tools to create users. In this documentation, we assume that this account is aquilon but you can use whatever name you want.

  • Create the keytab for the broker account:

      su - aquilon
      kinit with a principal who has Active Directory admin rights
      msktutil --update --use-service-account --keytab /var/spool/keytabs/aquilon --service aquilon \
               --account-name aquilon --user-creds-only
    
  • Restart the Aquilon broker

Note: msktutil initialises the Active Directory account password with a random value, thus this account cannot be used to run Aquilon client (aq command). Be sure to use another principal when initialising the Aquilon database (next step) to ensure that you have at least one usable Aquilon administrator.

Create the Aquilon directories

Aquilon requires a few directories to be created for its internal data, the log files, the templates and, if SQLite is used, for the database. All theses directories must be own by the aquilon account created before. Based on the default configuration proposed, use the following commands to create those directories. Adapt the directory paths to what you put in /etc/aqd.conf before.

```bash
mkdir /var/quattor
mkdir /var/quattor/domains
# The following directory is needed only if the SQLite back-end is used
mkdir /var/quattor/aquilondb
chown -R aquilon:aquilon /var/quattor
```

Initialise the Aquilon Database

To create the Aquilon database:

mkdir -p /var/quattor/aquilondb
chown -R aquilon:aquilon /var/quattor
su - aquilon
# Activate the VirtualEnv is one is used
. /var/quattor/aquilon-venv/bin/activate
# kinit user must be either `aquilon` if you use a standalone Kerberos server or
# another valid principal if you have a central infrastructure (including Active Directory)
kinit        # Enter the password you set previously
/opt/aquilon/tests/aqdb/build_db.py

Test The Broker

To test the broker, run /opt/aquilon/tests/dev_aqd.sh that must run successfully if your installation is correct. Before running this script, you need to define AQDCONF environment variable to /etc/aqd.conf (the script uses /etc/aqd.conf.dev by default).

To check that the broker is working properly, in another window, execute the following command:

/opt/aquilon/bin/aq.py status

The command should return some information on your current Aquilon environment, without any error. If this is the case, stop the broker started by the dev_aqd.sh script.

Start the Production Broker

To start the production broker, a systemd unit file must be added. A template is provided in /opt/aquilon/etc/systemd/aquilon-broker.service. Review its contents, in particular the Python interpreter path, before copying the file to /etc/systemd/system/multi-user.target.wants.

The aquilon broker service relies on /etc/sysconfig/aqd for its configuration. Create it from the template in /opt/aquilon/etc/sysconfig/aqd, changing TWISTD to /opt/aquilon/sbin/aqd.py and ensuring that other variables have a definition consistent with what is in /etc/aqd.conf.

Once this is done, use the following commands to add and start the broker service:

systemctl daemon-reload
systemctl start aquilon-broker
systemctl status aquilon-broker

Check the log file specified in /etc/sysconfig/aqd if systemctl status reports errors.

Git Daemon Configuration

Create a bare Git repository in ``/var/quattor/template-king that will be the master repository for the templates and create its prod` branch (which is expected to exist after the database initialisation but is not created):

git init --bare /var/quattor/template-king
cd /tmp
git clone /var/quattor/template-king
cd template-king
git checkout -b prod
# You can adjust the README contents if you want
echo "Aquilon templates master repository" > README.md
git add README.md
# If Git complains about missing user.email and user.name, define them (actual value does not matter)
git commit -am 'README added'
git push --set-upstream origin HEAD

By default Aquilon broker uses trash branch to take a snapshot of a domain before deleting it. If you wish to disable this functionality, leave trash_branch option in the [broker] configuration section blank. To use this feature (enabled by default), trash branch will need to be manually created as part of initial Git set up:

git push origin prod:trash

Then start the Git daemon and test it:

git daemon --export-all --base-path=/var /var/quattor/template-king &
# The following command must return something other than an error...
git ls-remote /quattor/template-king

When the git-daemon has been successfully tested, stop it (kill the process) and edit /etc/aqd.conf ([broker] section) to add the following configuration options if their default in /opt/aquilon/etc/aqd.conf.defaults is not appropriate:

  • Change run_git_daemon to True
  • Check that kingdir value resolves to the actual location of the template-king repository created previously
  • Check the git_daemon_basedir value: it must be the template-king repository path prefix to remove for the repository be accessible with the URL specified in git_templates_url (by default, //current_server/quattor/template_king)

Web Server Configuration

You need to configure the web server you installed so that the directory profilesdir (by default, /var/quattor/web/htdocs/profiles) is served by the web server. This is typically done by defining the document root to /var/quattor/web/htdocs/, so that profiles are served with the URL http(s)://broker.dom.ain/profiles. It is also recommended to enable/require https for downloading profile as it may contain sensitive information.

Refer to your web server documentation to know how to do the configuration. Depending on the web server used, the main configuration file is:

  • Apache: /etc/httpd/conf/httpd.conf
  • Nginx: /etc/nginx/nginx.conf

Configuring the AII server for Aquilon support

AII (deployment) server can be run on the same machine as the Aquilon broker or on a separate machine. In both cases, this requires the broker to be able to connect the AII server through SSH using the account specified by configuration option installfe_user(the broker account name by default) and, from this account, to execute the command aii-shellfe as root through sudo.

Main steps involved are:

  • If the AII server is not running on the broker host, on the AII server create the account matching installfe_user configuration option (the broker account name by default).
  • On the AII server, configure sudo to allow the created account to execute /usr/sbin/shellfe as root without entering a password. If the account is aquilon, this typically involves adding the following line with visudo:

      aquilon ALL= (root)     NOPASSWD:       /usr/sbin/aii-shellfe *
    
  • On the broker host, under the broker account, generate SSH keys and add the pub key to the authorized_keys file for the account created above on the AII server.

Enabling SELinux

SELinux can be used in enforcing mode on the server hosting the Aquilon broker. In addition to all the steps described above, it is necessary to adjust the SELinux type of a few directories, mainly:

  • The directory containing the template-king Git repository must have the SELinux type git_sys_content_t. This can be set with:

      chcon -R -t git_sys_content_t /var/quattor/template-king
    
  • The rundir directory (defined in /etc/aqd.conf or /opt/etc/aqd.conf/defaults) must have the SELinux type var_run_t. This can be set with:

      chcon -R -t var_run_t /var/quattor/run
    
  • The profilesdir directory (defined in /etc/aqd.conf or /opt/etc/aqd.conf/defaults) must have the SELinux type httpd_sys_content_t. This can be set with:

      chcon -R -t httpd_sys_content_t /var/quattor/web/htdocs
    

Upgrading Aquilon

Upgrading Aquilon involves updating both Aquilon protocols and Aquilon itself and sometimes a database schema upgrade. First step if to get the current version of Aquilon installed, using:

aq status

To upgrade Aquilon protocols and Aquilon itself, use Git to get the last version of each one, executing the following command in the directory containing the protocols sources and in /opt/aquilon:

git pull

For Aquilon protocols, follow the installation procedure above to rebuild and install the new version. Then, after updating Aquilon itself, restart the broker:

systemctl restart aquilon-broker

To determine if a database upgrade is needed, go to directory /opt/aquilon/upgrades and look for directory names matching a version greater than the one that was previously installed. If such directories exist, you need to execute the SQL scripts (and sometimes Python scripts) they contain in sequence. You need to use the script variant appropriate to your database back-end (Oracle and PostgreSQL supported). There is also a .backout script to revert the change if necessary. Look at the README for more details.

Note: up to version 1.12.58, there is no backout script and the SQL scripts are only for Oracle and may require some tweaking for SQLite and Postgres. In particular, SQLite has a very limited support for ALTER TABLE and doesn’t support in particular ATLER TABLE table MODIFY statement used to define a constraint. This produces an error that can be ignored.

Aquilon DB Configuration

See starting a site with Aquilon.

Troubleshooting

No known Aquilon administrator authorised

This may happen particularly if you executed build_db (database initialisation) with the aquilon principal when using Active Directory, as adding the entry in the keytab file will reset it password and changing the password afterwards will make the keytab file unsynchronized with Kerberos realm.

To workaround this and enable another existing AD account (Kerberos principal) to act as the Aquilon admin, you will need to execute the following steps on the database server using a user with modification rights on the Aquilon database. The broker must be running. The database commands given are for SQLite back-end, adapt them to your back-end (for Postgres, this typically involves executing psql -d aquilon -c "SQL command" instead of sqlite3 /var/quattor/aquilondb "SQL command").

  • su - to the aquilon account and execute kinit for the principal that you want to add as an Aquilon admin
  • Execute command aq.py status: it should return that the principal is mapped to role nobody
  • Assuming that the Aquilon DB is located in /var/quattor/aquilondb (see below) and that the principal user ID is aqadm, execute the following commands:
      # Retrieve the ID associated with the role `aqd_admin`
      admin_role_id=$(sqlite3 /var/quattor/aquilondb "select id from role where name='aqd_admin';")
      # Retrive the ID associated with the principal that you want to modify
      admin_pri_id=$(sqlite3 /var/quattor/aquilondb "select id from user_principal where name='aqadm';")
      # Check that both IDs are defined (non empty value)
      echo $admin_role_id
      echo $admin_pri_id
      # If they are defined, update the role associated with the principal
      sqlite3 /var/quattor/aquilondb "update user_principal set role_id=${admin_role_id} where id=${admin_pri_id};"