# OAR 2.6 documentation

## Installation

## Overview

There are currently 3 methods to install OAR:

> - from the Debian packages

> - from the RPM packages

> - from sources

Before going further, please have in mind OAR’s architecture. A common OAR installation is composed of:

> - a server which will hold all of OAR “smartness”. That host will run the OAR server daemon;

> - one or more frontends, which users will have to login to, in order to reserve computing nodes (oarsub, oarstat, oarnodes, …);

> - computing nodes (or basically nodes), where the jobs will execute;

> - optionally a visualisation server which will host the visualisation webapps (monika, drawgantt, …);

> - optionally an API server, which will host OAR restful API service.

Many OAR data are stored and archived in a database: you have the choice to use either PostgreSQL or MySQL. We recommend using PostgreSQL.

Beside this documentation, please have a look at OAR website: http://oar.imag.fr, which also provides a lot of information, espacially in the Download and Contribs sections.

## Computing nodes

### Installation from the packages

Instructions

For RedHat like systems:

    # OAR provides a Yum repository.
    # For more information see: http://oar.imag.fr/download#rpms

    # Install OAR node
    yum --enablerepo=OAR install oar-node

For the Debian like systems:

    # OAR is shipped as part of Debian official distributions (newer versions can be available in backports)
    # For more info see: http://oar.imag.fr/download#debian

    # Install OAR node
    apt-get install oar-node

### Installation from the tarball

Requirements

For RedHat like systems:

    # Build dependencies
    yum install gcc make tar python-docutils

    # Common dependencies
    yum install Perl Perl-base openssh

For Debian like system:

    # Build dependencies
    apt-get install gcc make tar python-docutils

    # Common dependencies
    apt-get install perl perl-base openssh-client openssh-server

Instructions

Get the sources:

    OAR_VERSION=2.5.4
    wget -O - http://oar-ftp.imag.fr/oar/2.5/sources/stable/oar-${OAR_VERSION}.tar.gz | tar xzvf -
    cd oar-${OAR_VERSION}/

build/install/setup:

    # build
    make node-build
    # install
    make node-install
    # setup
    make node-setup

### Configuration

#### Init.d scripts

If you have installed OAR from sources, you need to become root user and install manually the {init.d,default,sysconfig} scripts present in the folders:

    $PREFIX/share/doc/oar-node/examples/scripts/{init.d,default,sysconfig}

Then you just need to use the script `/etc/init.d/oar-node` to start the SSH daemon dedicated to oar-node.

#### SSH setup

OAR uses SSH to connect from machine to machine (e.g. from server or frontend to nodes or from nodes to nodes), using a dedicated SSH daemon usually running on port 6667.

Upon installtion of the OAR server on the server machine, a SSH key pair along with an authorized_keys file is created for the oar user in `/var/lib/oar/.ssh`. You need to copy that directory from the oar server to the nodes.

Please note that public key in the authorized_keys file must be prefixed with `environment="OAR_KEY=1"`, e.g.:

    environment="OAR_KEY=1" ssh-rsa AAAAB3NzaC1yc2[...]6mIcqvcwG1K7V6CHLQKHKWo/ root@server

Also please make sure that the `/var/lib/oar/.ssh` directory and contained files have the right ownership (oar.oar) and permissions for SSH to function.

## Server

### Installation from the packages

Instructions

For RedHat like systems:

    # OAR provides a Yum repository.
    # For more information see: http://oar.imag.fr/download#rpms

    # Install OAR server for the PostgreSQL backend
    yum --enablerepo=OAR install oar-server oar-server-pgsql

    # or Install OAR server for the MySQL backend
    yum --enablerepo=OAR install oar-server oar-server-mysql

For the Debian like systems:

    # OAR is shipped as part of Debian official distributions (newer versions can be available in backports)
    # For more info see: http://oar.imag.fr/download#debian

    # Install OAR server for the PostgreSQL backend
    apt-get install oar-server oar-server-pgsql

    # or Install OAR server for the MySQL backend
    apt-get install oar-server oar-server-mysql

### Installation from the tarball

Requirements

For RedHat like systems:

    # Add the epel repository (choose the right version depending on your
    # operating system)
    yum install epel-release

    # Build dependencies
    yum install gcc make tar python-docutils

    # Common dependencies
    yum install Perl Perl-base openssh Perl-DBI perl-Sort-Versions perl-Capture-Tiny

    # MySQL dependencies
    yum install mysql-server mysql perl-DBD-MySQL

    # PostgreSQL dependencies
    yum install postgresql-server postgresql perl-DBD-Pg

For Debian like system:

    # Build dependencies
    apt-get install gcc make tar python-docutils

    # Common dependencies
    apt-get install perl perl-base openssh-client openssh-server libdbi-perl libsort-versions-perl libcapture-tiny-perl

    # MySQL dependencies
    apt-get install mysql-server mysql-client libdbd-mysql-perl

    # PostgreSQL dependencies
    apt-get install postgresql postgresql-client libdbd-pg-perl

Instructions

Get the sources:

    OAR_VERSION=2.5.4
    wget -O - http://oar-ftp.imag.fr/oar/2.5/sources/stable/oar-${OAR_VERSION}.tar.gz | tar xzvf -
    cd oar-${OAR_VERSION}/

Build/Install/Setup the OAR server:

    # build
    make server-build
    # install
    make server-install
    # setup
    make server-setup

### Configuration

#### The oar database

Define the database configuration in /etc/oar/oar.conf. You need to set the variables `DB_TYPE, DB_HOSTNAME, DB_PORT, DB_BASE_NAME, DB_BASE_LOGIN, DB_BASE_PASSWD, DB_BASE_LOGIN_RO, DB_BASE_PASSWD_RO`:

    vi /etc/oar/oar.conf

Create the database and the database users:

    # General case
    oar-database --create --db-admin-user <ADMIN_USER> --db-admin-pass <ADMIN_PASS>

    # OR, for PostgreSQL, in case the database is installed locally
    oar-database --create --db-is-local

#### Init.d scripts

If you have installed OAR from sources, you need to become root user and install manually the init.d/default/sysconfig scripts present in the folders:

    $PREFIX/share/doc/oar-server/examples/scripts/{init.d,default,sysconfig}

Then use the script `/etc/init.d/oar-server` to start the OAR server daemon.

#### Adding resources to the system

To automatically initialize resources for your cluster, you can run the `oar_resources_init` command. It will detect the resources from nodes set in a file and give the OAR commands to initialize the database with the appropriate values for the memory and the cpuset properties.

Another tool is also available to create resources beforehand: that tool does not require nodes to be up and accessible by SSH. See `oar_resources_add`.

Otherwise:

To add resources to your system, you can use (as root) the `oarnodesetting` command. For a complete understanding of what that command does, see the manual page. For a basic usage, the main options are -a (means add a resource) and -h (defines the resource hostname or ip adress).

For instance, to add a computing resource for node <NODE_IP> to your setup, type:

    oarnodesetting -a -h <NODE_IP>

This adds a resource with <NODE_IP> as host IP address (network_address property).

You can modify resources properties with -p option, for instance:

    oarnodesetting -r 1 -p "besteffort=YES"

This allows the resource #1 to accept jobs of type besteffort (an admission rule forces besteffort jobs to execute on resources with the property “besteffort=YES”).

### Notes

#### Security issues

For security reasons it is hardly recommended to configure a read only account for the OAR database (like the above example). Thus you will be able to add it in DB_BASE_LOGIN_RO and DB_BASE_PASSWD_RO in oar.conf.

#### PostgreSQL: autovacuum

Be sure to activate the “autovacuum” feature in the “postgresql.conf” file (OAR creates and deletes a lot of records and this setting cleans the postgres database from unneeded records).

#### PostgreSQL: authentication

In case you’ve installed a PostgreSQL database remotely, if your PostgreSQL installation doesn’t authorize the local connections by default, you need to enable the connections to this database for the oar users. Assuming the OAR server has the address <OAR_SERVER>, you can add the following lines in the `pg_hba.conf` file:

    # in /etc/postgresql/8.1/main/pg_hba.conf or /var/lib/pgsql/data/pg_hba.conf
    host    oar         oar_ro            <OAR_SERVER>/32    md5
    host    oar         oar               <OAR_SERVER>/32    md5

#### Using Taktuk

If you want to use taktuk to manage remote administration commands, you have to install it. You can find information about taktuk from its website: http://taktuk.gforge.inria.fr.

Then, you have to edit your oar configuration file and fill in the related parameters:

> - `TAKTUK_CMD` (the path to the taktuk command)

> - `PINGCHECKER_TAKTUK_ARG_COMMAND` (the command used to check resources states)

> - `SCHEDULER_NODE_MANAGER_SLEEP_CMD` (command used for halting nodes)

#### CPUSET feature

OAR uses the CPUSET features provided by the Linux kernel >= 2.6. This enables to restrict user processes to reserved processors only and provides a powerful clean-up mechanism at the end of the jobs.

For more information, have a look at the CPUSET file.

#### Energy saving

Starting with version 2.4.3, OAR provides a module responsible of advanced management of wake-up/shut-down of nodes when they are not used. To activate this feature, you have to:

> - provide 2 commands or scripts which will be executed on the oar server to shutdown (or set into standby) some nodes and to wake-up some nodes (configure the path of those commands into the `ENERGY_SAVING_NODE_MANAGER_WAKE_UP_CMD` and `ENERGY_SAVING_NODE_MANAGER_SHUT_DOWN_CMD` variables in oar.conf) Thes 2 commands are executed by the oar user.

> - configure the `available_upto` property of all your nodes:

>   - `available_upto=0` : to disable the wake-up and halt

>   - `available_upto=1` : to disable the wake-up (but not the halt)

>   - `available_upto=2147483647` : to disable the halt (but not the wake-up)

>   - `available_upto=2147483646` : to enable wake-up/halt forever

>   - `available_upto=<timestamp>` : to enable the halt, and the wake-up until the date given by <timestamp>

>   Ex: to enable the feature on every nodes forever:

>         oarnodesetting --sql true -p available_upto=2147483646

> - activate the energy saving module by setting `ENERGY_SAVING_INTERNAL="yes"` and configuring the `ENERGY_*` variables into oar.conf

> - configure the metascheduler time values into `SCHEDULER_NODE_MANAGER_IDLE_TIME`, `SCHEDULER_NODE_MANAGER_SLEEP_TIME` and `SCHEDULER_NODE_MANAGER_WAKEUP_TIME` variables of the oar.conf file.

> - restart the oar server (you should see an “Almighty” process more).

You need to restart OAR each time you change an `ENERGY_*` variable. More informations are available inside the oar.conf file itself. For more details about the mechanism, take a look at the “Hulot” module documentation.

#### Disabling SELinux

On some distributions, SELinux is enabled by default. There is currently no OAR support for SELinux. So, you need to disable SELinux, if enabled.

#### Cpuset id issue

On some rare servers, the core ids are not persistent across reboot. So you need to update the cpuset ids in the resource database at startup for each computing node. You can do this by using the `/etc/oar/update_cpuset_id.sh` script. The following page give more informations on how configuring it:

> http://oar.imag.fr/wiki:old:customization_tips#start_stop_of_nodes_using_ssh_keys

## Frontends

### Installation from the packages

Instructions

For RedHat like systems:

    # OAR provides a Yum repository.
    # For more information see: http://oar.imag.fr/download#rpms

    # Install OAR user for the PostgreSQL backend
    yum --enablerepo=OAR install oar-user oar-user-pgsql

    # or Install OAR user for the MySQL backend
    yum --enablerepo=OAR install oar-user oar-user-mysql

For the Debian like systems:

    # OAR is shipped as part of Debian official distributions (newer versions can be available in backports)
    # For more info see: http://oar.imag.fr/download#debian

    # Install OAR server for the PostgreSQL backend
    apt-get install oar-user oar-user-pgsql

    # or Install OAR server for the MySQL backend
    apt-get install oar-user oar-user-mysql

### Installation from the tarball

Requirements

For RedHat like systems:

    # Build dependencies
    yum install gcc make tar python-docutils

    # Common dependencies
    yum install Perl Perl-base openssh Perl-DBI

    # MySQL dependencies
    yum install mysql perl-DBD-MySQL

    # PostgreSQL dependencies
    yum install postgresql perl-DBD-Pg

For Debian like system:

    # Build dependencies
    apt-get install gcc make tar python-docutils

    # Common dependencies
    apt-get install perl perl-base openssh-client openssh-server libdbi-perl

    # MySQL dependencies
    apt-get install mysql-client libdbd-mysql-perl

    # PostgreSQL dependencies
    apt-get install postgresql-client libdbd-pg-perl

Instructions

Get the sources:

    OAR_VERSION=2.5.4
    wget -O - http://oar-ftp.imag.fr/oar/2.5/sources/stable/oar-${OAR_VERSION}.tar.gz | tar xzvf -
    cd oar-${OAR_VERSION}/

Build/Install/setup:

    # build
    make user-build
    # install
    make user-install
    # setup
    make user-setup

### Configuration

#### SSH setup

OAR uses SSH to connect from machine to machine (e.g. from server or frontend to nodes or from nodes to nodes), using a dedicated SSH daemon usually running on port 6667.

Upon installtion of the OAR server on the server machine, a SSH key pair along with an authorized_keys file is created for the oar user in `/var/lib/oar/.ssh`. You need to copy that directory from the oar server to the frontend (if not the same machine).

Please note that public key in the authorized_keys file must be prefixed with `environment="OAR_KEY=1"`, e.g.:

    environment="OAR_KEY=1" ssh-rsa AAAAB3NzaC1yc2[...]6mIcqvcwG1K7V6CHLQKHKWo/ root@server

Also please make sure that the `/var/lib/oar/.ssh` directory and contained files have the right ownership (oar.oar) and permissions for SSH to function.

#### Coherent configuration files between server node and user nodes

You need to have a coherent oar configuration between the server node and the user nodes. So you can just copy the /etc/oar/oar.conf directory from to server node to the user nodes.

#### About X11 usage in OAR

The easiest and scalable way to use X11 application on cluster nodes is to open X11 ports and set the right DISPLAY environment variable by hand. Otherwise users can use X11 forwarding via SSH to access cluster frontends. You must configure the SSH server on the frontends nodes with:

    X11Forwarding yes
    X11UseLocalhost no

With this configuration, users can launch X11 applications after a ‘oarsub -I’ on the given node or “oarsh -X node12”.

## API server

### Description

Since the version 2.5.3, OAR offers an API for users and admins interactions. This api must be installed on a frontend node (with the user module installed).

### Installation from the packages

Instructions

For RedHat like systems:

    # OAR provides a Yum repository.
    # For more information see: http://oar.imag.fr/download#rpms

    # Install apache FastCGI and Suexec modules (optional but highly recommended)

    # Install OAR Restful api
    yum --enablerepo=OAR install oar-restful-api

For the Debian like systems:

    # OAR is shipped as part of Debian official distributions (newer versions can be available in backports)
    # For more info see: http://oar.imag.fr/download#debian

    # Install apache FastCGI and Suexec modules (optional but highly recommended)

    # Install OAR Restful api
    apt-get install oar-restful-api

### Installation from the tarball

Requirements

For RedHat like systems:

    # Build dependencies
    yum install gcc make tar python-docutils

    # Common dependencies
    yum install perl perl-base perl-DBI perl-CGI perl-JSON perl-YAML perl-libwww-perl httpd

    # Install apache FastCGI and Suexec modules (optional but highly recommended)

    # MySQL dependencies
    yum install perl-DBD-MySQL

    # PostgreSQL dependencies
    yum install perl-DBD-Pg

For Debian like system:

    # Build dependencies
    apt-get install gcc make tar python-docutils

    # Common dependencies
    apt-get install perl perl-base libdbi-perl libjson-perl libyaml-perl libwww-perl apache2 libcgi-fast-perl

    # Install apache FastCGI and Suexec modules (optional but highly recommended)

    # MySQL dependencies
    apt-get install libdbd-mysql-perl

    # PostgreSQL dependencies
    apt-get install libdbd-pg-perl

Instructions

Get the sources:

    OAR_VERSION=2.5.4
    wget -O - http://oar-ftp.imag.fr/oar/2.5/sources/stable/oar-${OAR_VERSION}.tar.gz | tar xzvf -
    cd oar-${OAR_VERSION}/

build/install/setup:

    # build
    make api-build
    # install
    make api-install
    # setup
    make api-setup

### Configuration

Configuring OAR

> For the moment, the API needs the user tools to be installed on the same host (’`make user-install`’ or oar-user packages). A suitable `/etc/oar/oar.conf` should be present. For the API to work, you should have the oarstat/oarnodes/oarsub commands to work (on the same host you installed the API)

Configuring Apache

> The api provides a default configuration file (`/etc/oar/apache-api.conf`) that is using an identd user identification enabled only from localhost. Edit the `/etc/oar/apache-api.conf` file and customize it to reflect the authentication mechanism you want to use. For ident, you may have to install a “identd” daemon on your distrib. The steps may be:

> > - Install and run an identd daemon on your server (like pidentd).

> > - Activate the ident auth mechanism into apache (`a2enmod ident`).

> > - Activate the headers apache module (`a2enmod headers`).

> > - Activate the rewrite apache module (`a2enmod rewrite`).

> > - Customize apache-api.conf to allow the hosts you trust for ident.

YAML, JSON, XML

> You need at least one of the YAML or JSON perl module to be installed on the host running the API.

Test

> You may test the API with a simple wget:

>     wget -O - http://localhost/oarapi/resources.html

> It should give you the list of resources in the yaml format but enclosed in an html page. To test if the authentication works, you need to post a new job. See the example.txt file that gives you example queries with a ruby rest client.

## Visualization server

### Description

OAR provides two webapp tools for visualizing the resources utilization:

    - monika which displays the current state of resources as well as all running and waiting jobs
    - drawgantt-svg which displays gantt chart of nodes and jobs for the past and future.

### Installation from the packages

Instructions

For RedHat like systems:

    # OAR provides a Yum repository.
    # For more information see: http://oar.imag.fr/download#rpms

    # Install OAR web status package
    yum --enablerepo=OAR install oar-web-status

For the Debian like systems:

    # OAR is shipped as part of Debian official distributions (newer versions can be available in backports)
    # For more info see: http://oar.imag.fr/download#debian

    # Install OAR web status package
    apt-get install oar-web-status

### Installation from the tarball

Requirements

For RedHat like systems:

    # Build dependencies
    yum install gcc make tar python-docutils

    # Common dependencies
    yum install perl perl-base perl-DBI ruby-GD ruby-DBI perl-Tie-IxHash perl-Sort-Naturally perl-AppConfig php

    # MySQL dependencies
    yum install mysql perl-DBD-MySQL ruby-mysql php-mysql

    # PostgreSQL dependencies
    yum install postgresql perl-DBD-Pg ruby-pg php-pgsql

For Debian like system:

    # Build dependencies
    apt-get install gcc make tar python-docutils

    # Common dependencies
    apt-get install perl perl-base ruby libgd-ruby1.8 libdbi-perl libtie-ixhash-perl libappconfig-perl libsort-naturally-perl libapache2-mod-php5

    # MySQL dependencies
    apt-get install libdbd-mysql-perl libdbd-mysql-ruby php5-mysql

    # PostgreSQL dependencies
    apt-get install libdbd-pg-perl libdbd-pg-ruby php5-pgsql

Instructions

Get the sources:

    OAR_VERSION=2.5.4
    wget -O - http://oar-ftp.imag.fr/oar/2.5/sources/stable/oar-${OAR_VERSION}.tar.gz | tar xzvf -
    cd oar-${OAR_VERSION}/

build/install/setup:

    # build
    make monika-build drawgantt-build drawgantt-svg-build www-conf-build
    # install
    make monika-install drawgantt-install drawgantt-svg-install www-conf-install
    # setup
    make monika-setup drawgantt-setup drawgantt-svg-setup www-conf-setup

### Configuration

Monika configuration

> - Edit `/etc/oar/monika.conf` to fit your configuration.

Drawgantt-SVG configuration

> - Edit `/etc/oar/drawgantt-config.inc.php` to fit your configuration.

httpd configuration

> - You need to edit `/etc/oar/apache.conf` to fit your needs and verify that you http server configured.