Yorc Supported infrastructures

This section describes the state of our integration with supported infrastructures and their specificities

Hosts Pool

The Hosts Pool is a very special kind of infrastructure. It consists in registering existing Compute nodes into a pool managed by Yorc. Those compute nodes could be physical or virtual machines, containers or whatever as long as Yorc can SSH into it. Yorc will be responsible to allocate and release hosts for deployments. This is safe to use it concurrently in a Yorc cluster, Yorc instances will synchronize amongst themselves to ensure consistency of the pool.

To sum up this infrastructure type is really great when you want to use an infrastructure that is not yet supported by Yorc. Just take care you’re responsible for handling the compatibility or conflicts of what is already installed and what will be by Yorc on your hosts pool. The best practice is using container isolation. This is especially true if a host can be shared by several apps by specifying in Tosca with the Compute shareable property.

Hosts management

Yorc comes with a REST API that allows to manage hosts in the pool and to easily integrate it with other systems. The Yorc CLI leverage this REST API to make it user friendly, please refer to CLI Commands related to hosts pool for more information

Hosts Pool labels & filters

It is strongly recommended to associate labels to your hosts. Labels allow to filter hosts based on criteria. Labels are just a couple of key/value pair

Filters Grammar

There are four kinds of filters supported by Yorc:

• Filters based on the presence of a label label_identifier will match if a label with the given name is associated with a host whatever its value is.
• Filters based on equality to a value label_identifier (=|==|!=) value will match if the value associated with the given label is equals (= and ==) or different (!=) to the given value
• Filters based on sets label_identifier (in | not in) (value [, other_value]) will match if the value associated with the given label is one (in) or is not one (not in) of the given values
• Filters based on comparisons label_identifier (< | <= | > | >=) number[unit] will match if the value associated with the given label is a number and matches the comparison sign. A unit could be associated with the number, currently supported units are golang durations (“ns”, “us” , “ms”, “s”, “m” or “h”), bytes units (“B”, “KiB”, “KB”, “MiB”, “MB”, “GiB”, “GB”, “TiB”, “TB”, “PiB”, “PB”, “EiB”, “EB”) and International System of Units (SI). The case of the unit does not matter.

Here are some example:

• gpu
• os.distribution != windows
• os.architecture == x86_64
• environment = "Q&A"
• environment in ( "Q&A", dev, edge)
• gpu.type not in (k20, m60)
• gpu_nb > 1
• os.mem_size >= 4 GB
• os.disk_size < 1tb
• max_allocation_time <= 120h

Implicit filters & labels

TOSCA allows to specify requirements on Compute hardware and Compute operating system . These are capabilities named host and os in the TOSCA node Compute . If those are specified in the topology, Yorc will automatically add a filter host.<property_name> >= <property_value> <property_unit> or os.<property_name> = <property_value> This will allow to select hosts matching the required criteria.

This means that it is strongly recommended to add the following labels to your hosts:

• host.num_cpus (ie. host.num_cpus=4)
• host.cpu_frequency (ie. host.cpu_frequency=3 GHz)
• host.disk_size (ie. host.disk_size=50 GB)
• host.mem_size (ie. host.mem_size=4GB)
• os.architecture (ie. os.architecture=x86_64)
• os.type (ie. os.type=linux)
• os.distribution (ie. os.distribution=ubuntu)
• os.version (ie. os.version=17.10)

Some labels are also automatically exposed as TOSCA Compute instance attributes:

• if present a label named private_address will be used as attribute private_address and ip_address of the Compute. If not set the connection host will be used instead this allows to specify a network different for the applicative communication and for the orchestrator communication
• if present a label named public_address will be used as attribute public_address of the Compute.
• if present, following labels will fill the networks attribute of the Compute node:
  • networks.<idx>.network_name (ie. networks.0.network_name)
  • networks.<idx>.network_id (ie. networks.0.network_id)
  • networks.<idx>.addresses as a coma separated list of addresses (ie. networks.0.addresses)

The resources host pool labels (host.num_cpus, host.disk_size, host.mem_size) are automatically decreased and increased respectively when a host pool is allocated and released only if you specify any of these Tosca host resources capabilities Compute in its Alien4Cloud applications. If you apply a new configuration on allocated hosts with new host resources labels, they will be recalculated depending on existing allocations resources.

Slurm

Slurm is an open source, fault-tolerant, and highly scalable cluster management and job scheduling system for large and small Linux clusters. It is wildly used in High Performance Computing and it is the default scheduler of the Bull Super Computer Suite .

Yorc interacts with Slurm to allocate nodes on its cluster but also to run Slurm jobs.

Jobs have been modeled in Tosca and this allows Yorc to execute them, either as simple jobs or as Singularity jobs.

Singularity is a container system similar to Docker but designed to integrate well HPC environments. and let users execute a command inside a Singularity or Docker container as a job submission. See Working with jobs for more information.

Yorc supports the following resources on Slurm:

• Node Allocations as Computes
• Jobs
• Singularity Jobs.

Resources based scheduling

TOSCA allows to specify requirements on Compute nodes if specified num_cpus and mem_size requirements are used to allocate only the required resoures on computes. This allows to share a Slurm managed compute across several deployments. If not specified a whole compute node will be allocated.

Yorc also support Slurm GRES based scheduling. This is generally used to request a host with a specific type of resource (consumable or not) such as GPUs.

Google Cloud Platform

The Google Cloud Platform integration within Yorc is ready for production and we support the following resources:

• Compute Instances
• Persistent Disks
• Virtual Private Clouds (VPC)
• Static IP Addresses.

Future work

It is planned to support soon the following feature:

• Cloud VPN

AWS

The AWS integration within Yorc allows to provision:

• EC2 Compute Instances.
• Elastic IPs.

This part is ready for production but we plan to support soon the following features to make it production-ready:

• Elastic Block Store provisioning
• Networks provisioning with Virtual Private Cloud

Future work

• We plan to work on modeling AWS Batch Jobs in TOSCA and execute them thanks to Yorc.
• We plan to work on AWS ECS to deploy containers

OpenStack

The OpenStack integration within Yorc is production-ready. Yorc is currently supporting:

• Compute Instances
• Block Storages
• Virtual Networks
• Floating IPs provisioning.

Future work

• We plan to work on modeling OpenStack Mistral workflows in TOSCA and execute them thanks to Yorc.
• We plan to work on OpenStack Zun to deploy containers directly on top of OpenStack

Kubernetes

The Kubernetes integration within Yorc is now production-ready. Yorc is currently supporting the following K8s resources:

• Deployments.
• Jobs.
• Services.

The Google Kubernetes Engine is also supported as a Kubernetes cluster.

Future work

It is planned to support soon the following features:

• Persistent Volume Claims.
• StatefulSets.