All the information about how to access a cloud provider and how to setup a cluster is stored in a configuration file. The default configuration file is stored in your home directory: ~/.elasticluster/config but you can specify a different location from the command line with the -c option.
When elasticluster is run for the first time, if no configuration file is found it will copy a template configuration file in ~/.elasticluster/config. Such template is fully commented and self documented.
The file is parsed by ConfigParser module and has a syntax similar to Microsoft Windows INI files.
It consists of sections led by a [sectiontype/name] header and followed by lines in the form:
Section names are in the form [type/name] wher type must be one of:
You must define at least one for each section types in order to have a valid configuration file.
A cloud section named <name> starts with:
The cloud section defines all properties needed to connect to a specific cloud provider.
You can define as many cloud sections you want, assuming you have access to different cloud providers and want to deploy different clusters in different clouds. The mapping between cluster and cloud provider is done in the cluster section (see later).
Currently two cloud providers are available: - boto: supports OpenStack and Amazon EC2 - google: supports Google Compute Engine Therefore the following configuration option needs to be set in the cloud section:
the driver to use to connect to the cloud provider. boto or google
the url of the EC2 endpoint. For Amazon is probably something like:https://ec2.us-east-1.amazonaws.com
replace us-east-1 with the zone you want to use while for OpenStack you can get it from the web interface
the access key (also known as access id) your cloud provider gave you to access its cloud resources.
the secret key (also known as secret id) your cloud provider gave you to access its cloud resources.
the availability zone you want to use.
The API client id generated in the Google API Console
The API client secret generated in the Google API Console
The project id of your Google Compute Engine project
[cloud/hobbes] provider=ec2_boto ec2_url=http://hobbes.gc3.uzh.ch:8773/services/Cloud ec2_access_key=****REPLACE WITH YOUR ACCESS ID**** ec2_secret_key=****REPLACE WITH YOUR SECRET KEY**** ec2_region=nova
For Amazon instead (region us-east-1) you can use:
[cloud/amazon-us-east-1] provider=ec2_boto ec2_url=https://ec2.us-east-1.amazonaws.com ec2_access_key=****REPLACE WITH YOUR ACCESS ID**** ec2_secret_key=****REPLACE WITH YOUR SECRET KEY**** ec2_region=us-east-1
For Google Compute Engine you can use:
[cloud/google] provider=google gce_client_id=****REPLACE WITH YOUR CLIENT ID**** gce_client_secret=****REPLACE WITH YOUR SECRET KEY**** gce_project_id=****REPLACE WITH YOUR PROJECT ID****
From the horizon web interface you can download a file containing your EC2 credentials by logging in in your provider web interface and clicking on:
The ec2rc.sh file will contain some values. Update the configuration file:
ec2_url using the value of the variable EC2_URL ec2_access_key using the value of the variable EC2_ACCESS_KEY ec2_secret_key using the value of the variable EC2_SECRET_KEY
To generate a client_id and client_secret to access the Google Compute Engine visit the following page: https://code.google.com/apis/console/ 1. Select the project defined as gce_project_id 2. Navigate to API Access 3. Click create another client id 4. Select Installed Application -> Other 5. After clicking the Create button you’ll see your client_id and
secret_key in the list of available client ids
A login section named <name> starts with:
This section contains information on how to access the instances started on the cloud, including the user and the SSH keys to use.
Some of the values depend on the image you specified in the cluster section. Values defined here also can affect the setup section and the way the system is setup.
the remote user you must use to connect to the virtual machine. In case you’re using Google Compute Engine you have to set your usernamehere. So if your gmail address is firstname.lastname@example.org, your username is karl.marx
Can be True or False. True means that on the remote machine you can execute commands as root by running the sudo program.
the login name of the administrator. Use root unless you know what you are doing...
name of the keypair to use on the cloud provider. If the keypair does not exist it will be created by elasticluster.
file containing a valid RSA or DSA private key to be used to connect to the remote machine. Please note that this must match the user_key_public file (RSA and DSA keys go in pairs). Also note that Amazon does not accept DSA keys but only RSA ones.
file containing the RSA/DSA public key corresponding to the user_key_private private key. See user_key_private for more details.
For a typical Ubuntu machine, both on Amazon and most OpenStack providers, these values should be fine:
[login/ubuntu] image_user=ubuntu image_user_sudo=root image_sudo=True user_key_name=elasticluster user_key_private=~/.ssh/id_rsa user_key_public=~/.ssh/id_rsa.pub
while for Hobbes appliances you will need to use the gc3-user instead:
[login/gc3-user] image_user=gc3-user image_user_sudo=root image_sudo=True user_key_name=elasticluster user_key_private=~/.ssh/id_rsa user_key_public=~/.ssh/id_rsa.pub
A setup section named <name> starts with:
This section contain information on how to setup a cluster. After the cluster is started, elasticluster will run a setup provider in order to configure it.
the type of setup provider. So far, only ansible is supported.
The following configuration keys are only valid if provider is ansible.
Comma separated list of ansible groups the specific <class> will belong to. For each <class>_nodes in a [cluster/] section there should be a <class>_groups option to configure that specific class of nodes with the ansible groups specified.
If you are setting up a standard HPC cluster you probably want to have only two main groups: frontend_groups and compute_groups.
To configure a slurm cluster, for instance, you have the following available groups:
- configure this machine as slurm masternode
- compute nodes of a slurm cluster
- configure as ganglia web frontend. On the master, you probably want to define ganglia monitor as well
- configure as ganglia monitor.
You can combine more groups together, but of course not all combinations make sense. A common setup is, for instance:frontend_groups=slurm_master,ganglia_master,ganglia_monitor compute_groups=slurm_clients,ganglia_monitor
This will configure the frontend node as slurm master and ganglia frontend, and the compute nodes as clients for both slurm and ganglia frontend.
A full list of the available groups is available at the Playbooks distributed with elasticluster page.
an entry of this type will define a variable called <varname> for the specific <class> and add it to the ansible inventory file.
Path to the playbook to use when configuring the system. The default value printed here points to the playbook distributed with elasticluster. The default value points to the playbooks distributed with elasticluster.
Some (working) examples:
[setup/ansible-slurm] provider=ansible frontend_groups=slurm_master compute_groups=slurm_clients [setup/ansible-gridengine] provider=ansible frontend_groups=gridengine_master compute_groups=gridengine_clients [setup/ansible-pbs] provider=ansible frontend_groups=pbs_master,maui_master compute_groups=pbs_clients [setup/ansible_matlab] # Please note that this setup assumes you already have matlab # installed on the image that is being used. provider=ansible frontend_groups=mdce_master,mdce_worker,ganglia_monitor,ganglia_master worker_groups=mdce_worker,ganglia_monitor
A cluster section named <name> starts with:
The cluster section defines a template for a cluster. This section has references to each one of the other sections and define the image to use, the default number of compute nodes and the security group.
the name of a valid cloud section. For instance hobbes or amazon-us-east-1
the name of a valid login section. For instance ubuntu or gc3-user
the name of a valid setup section. For instance, ansible-slurm or ansible-pbs
image id in ami format. If you are using OpenStack, you need to run euca-describe-images to get a valid ami-* id.
the image type to use. Different cloud providers call it differently, could be instance type, instance size or flavor.
Security group to use when starting the instance.
the number of nodes of type <class>. These configuration options will define the composition of your cluster. A very common configuration will include only two group of nodes:
- the queue manager and frontend of the cluster. You probably want only one.
- the worker nodes of the cluster.
Each <class>_nodes group is configured using the corresponding <class>_groups configuration option in the [setup/...] section.
ssh and sftp nodes will connect to only one node. This is the first of the group specified in this configuration option, or the first node of the first group in alphabetical order. For instance, if you don’t set any value for ssh_to and you defined two groups: frontend_nodes and compute_nodes, the ssh and sftp command will connect to compute001 which is the first compute_nodes node. If you specify frontend, instead, it will connect to frontend001 (or the first node of the frontend group).
shell script to be executed (as root) when the machine starts. This is usually not needed because the ansible provider works on vanilla images, but if you are using other setup providers you may need to execute some command to bootstrap it.
Some (working) examples:
[cluster/slurm] cloud=hobbes login=gc3-user setup_provider=ansible-slurm security_group=default # Ubuntu image image_id=ami-00000048 flavor=m1.small frontend_nodes=1 compute_nodes=2 frontend_class=frontend [cluster/torque] cloud=hobbes frontend_nodes=1 compute_nodes=2 frontend_class=frontend security_group=default # CentOS image image_id=ami-0000004f flavor=m1.small login=gc3-user setup_provider=ansible-pbs [cluster/aws-slurm] cloud=amazon-us-east-1 login=ubuntu setup_provider=ansible-slurm security_group=default # ubuntu image image_id=ami-90a21cf9 flavor=m1.small frontend=1 compute=2 [cluster/matlab] cloud=hobbes setup_provider=ansible_matlab security_group=default image_id=ami-00000099 flavor=m1.medium frontend_nodes=1 worker_nodes=10 image_userdata= ssh_to=frontend
A cluster node for the node type <nodetype> of the cluster <name> starts with:
This section allows you to override some configuration values for specific group of nodes. Assume you have a standard slurm cluster with a frontend which is used as manager node and nfs server for the home directories, and a set of compute nodes.
You may want to use different flavors for the frontend and the compute nodes, since for the first you need more space and you don’t need many cores or much memory, while the compute nodes may requires more memory and more cores but are not eager about disk space.
This is achieved defining, for instance, a bigdisk flavor (the name is just fictional) for the frontend and 8cpu32g for the compute nodes. Your configuration will thus look like:
[cluster/slurm] ... flavor=8cpu32g frontend_nodes=1 compute_nodes=10 [cluster/slurm/frontend] flavor=bigdisk