Evaluate container lifecycle support in TOSCA

TOSCA – 174 Adhoc TC

• Evaluate various types of containers support for TOSCA – Full OS containers (compute node)

• VM• LXC

– Application containers• Docker• PaaS containers

• Evaluation context for container support– Mutability – Supported– Resource Isolation policies – Supported through Node types– Deployment methods – Supported through plans– Container types – Supported through node types

Container Types

TOSCA 174 - Evaluate container lifecycle support in TOSCA

Container Abstraction

Should container be represented by Node Type in Topology template OR is it an deployment abstraction?

• Container is a Node type • Containment is a tree structure in TOSCA

– Supported by requirements and capabilities

• Various types of container are supported– Compute node (Full OS) – Application container

• Nested containers are a modeling construct and supported• Container placement control is currently not supported

TOSCA 174 - Evaluate container lifecycle support in TOSCA

Use sample containers to build TOSCA service template• Pick one Full OS and one application container• Create 2 tier application topology• Map lifecycle of these containers• Identify constraints and challenges

Observations:• Networking of containers

– Inter host communication through bridge on OpenStack could be a problem with Docker containers (multi node stack)

Workaround• Workaround using Port forward from host to Docker• OVS bridge between hosts with containers getting private ip address with bridged with local host

• Container is represented by NodeType, currently there is no way to abstract a container to avoid node proliferation

Workarounds• Create new type for each image • Or define capabilities & requirements on the template

Link to Sample use case:https://docs.google.com/a/canonical.com/document/d/17TMNmlDKI_HcKSuFtsPPqOk8PqcWpPNGoydtqw-uLgM/edit

Use Cases

TOSCA 174 - Evaluate container lifecycle support in TOSCA

• Map container lifecycle events to TOSCA

Typical container events• deploy/init/stop/dispose(Runtime)• build/modify/delete (devtime) – Not covered by TOSCA • Multi host environment

TOSCA events• create/pre-configure/configure/post-configure/start/stop

TOSCA events are superset of typical container events

Container Lifecycle mapping

TOSCA 174 - Evaluate container lifecycle support in TOSCA

• 5> Discuss support for composite nodes (specifically immutable containers), and avoid node proliferation through node decoration

Support for Composite nodes

TOSCA 174 - Evaluate container lifecycle support in TOSCA