Skip to content

Latest commit

 

History

History
115 lines (97 loc) · 5.18 KB

kata-api-design.md

File metadata and controls

115 lines (97 loc) · 5.18 KB
Raw

Kata API Design

To fulfill the kata design requirements, and based on the disscusion on Virtcontainers API extentions, the kata runtime library features the following APIs:

  • Sandbox based top API
  • Storage and network hotplug API
  • Plugin frameworks for external proprietary Kata runtime extensions
  • Built-in shim and proxy types and capabilities

Sandbox Based API

Sandbox Management API

Name Description
CreateSandbox(SandboxConfig) Create and start a sandbox, and return the sandbox structure.
FetchSandbox(ID) Connect to an existing sandbox and return the sandbox structure.
ListSandboxes() List all existing standboxes with status.

Sandbox Operation API

Name Description
sandbox.Pause() Pause the sandbox.
sandbox.Resume() Resume the paused sandbox.
sandbox.Release() Release a sandbox data structure, close connections to the agent, and quit any goroutines associated with the sandbox. Mostly used for daemon restart.
sandbox.Delete() Destroy the sandbox and remove all persistent metadata.
sandbox.Status() Get the status of the sandbox and containers.
sandbox.Monitor() Return a context handler for caller to monitor sandbox callbacks such as error termination.
sandbox.CreateContainer() Create new container in the sandbox.
sandbox.DeleteContainer() Delete a container from the sandbox.
sandbox.StartContainer() Start a container in the sandbox.
sandbox.StatusContainer() Get the status of a container in the sandbox.
sandbox.EnterContainer() Run a new process in a container.
sandbox.WaitProcess() Wait on a process to terminate.

Sandbox Hotplug API

Name Description
sandbox.AddDevice() Add new storage device to the sandbox.
sandbox.AddInterface() Add new nic to the sandbox.
sandbox.RemoveInterface() Remove a nic from the sandbox.
sandbox.ListInterfaces() List all nics and their configurations in the sandbox.
sandbox.UpdateRoutes() Update the sandbox route table (e.g. for portmapping support).
sandbox.ListRoutes() List the sandbox route table.

Sandbox Relay API

Name Description
sandbox.WinsizeProcess(containerID, processID, Height, Width) Relay TTY resize request to a process.
sandbox.SignalProcess(containerID, processID, signalID, signalALL) Relay a signal to a process or all processes in a container.
sandbox.IOStream(containerID, processID) Relay a process stdio. Return stdin/stdout/stderr pipes to the process stdin/stdout/stderr streams.

Plugin framework for external proprietary Kata runtime extensions

Hypervisor plugin

TBD.

Metadata storage plugin

The metadata storage plugin controls where sandbox metadata is saved. All metadata storage plugins must implement the following API:

Name Description
storage.Save(key, value) Save a record.
storage.Load(key) Load a record.
storage.Delete(key) Delete a record.

Built-in implementations include:

  • Filesystem storage
  • LevelDB storage

VM Factory plugin

The VM factory plugin controls how a sandbox factory creates new VMs. All VM factory plugins must implement following API:

Name Description
VMFactory.NewVM(HypervisorConfig) Create a new VM based on HypervisorConfig.

Built-in implementations include:

Name Description
CreateNew() Create brand new VM based on 'HypervisorConfig'.
CreateFromTemplate() Create new VM from template.
CreateFromCache() Create new VM from VM caches.

Sandbox Creation Plugin Workflow

Sandbox Creation Plugin Workflow

Sandbox Connection Plugin Workflow

Sandbox Connection Plugin Workflow

Built-in Shim and Proxy Types and Capabilities

Built-in shim/proxy sandbox configurations

  • Supported shim configurations:
Name Description
noopshim Do not start any shim process.
ccshim Start the cc-shim binary.
katashim Start the kata-shim binary.
katashimbuiltin No standalone shim process but shim functionality APIs are exported.
  • Supported proxy configurations:
Name Description
noopProxy a dummy proxy implementation of the proxy interface, only used for testing purpose.
noProxy generic implementation for any case where no actual proxy is needed.
ccProxy run ccProxy to proxy between runtime and agent.
kataProxy run kata-proxy to translate yamux connections between runtime and kata agent.
kataProxyBuiltin no standalone proxy process and connect to kata agent with internal yamux translation.

Built-in Shim Capability

Built-in shim capability is implemented by removing standalone shim process, and supporting the shim related APIs.

Built-in Proxy Capability

Built-in proxy capability is achieved by removing standalone proxy process, and connecting to kata agent with a custom grpc dialer that is internal yamux translation. The behavior is enabled when proxy is configured as kataProxyBuiltin.