upgrades

Documentation

Overview

The upgrades package provides infrastructure to upgrade previous Juju deployments to the current Juju version. The upgrade is performed on a per node basis, across all of the running Juju machines.

Important exported APIs include:

PerformUpgrade, which is invoked on each node by the machine agent with:
  fromVersion - the Juju version from which the upgrade is occurring
  target      - the type of Juju node being upgraded
  context     - provides API access to Juju state servers

Index

• Constants
• func PerformUpgrade(from version.Number, target Target, context Context) error
• type Context
  • func NewContext(agentConfig agent.Config, api *api.State, st *state.State) Context
• type Operation
• type Step
• type Target

Constants

const (
	// AllMachines applies to any machine.
	AllMachines = Target("allMachines")

	// HostMachine is a machine on which units are deployed.
	HostMachine = Target("hostMachine")

	// StateServer is a machine participating in a Juju state server cluster.
	StateServer = Target("stateServer")
)

Functions

func PerformUpgrade

func PerformUpgrade(from version.Number, target Target, context Context) error

PerformUpgrade runs the business logic needed to upgrade the current "from" version to this version of Juju on the "target" type of machine.

Types

type Context

type Context interface {
	// APIState returns an API connection to state.
	APIState() *api.State

	// State returns a connection to state. This will be non-nil
	// only in the context of a state server.
	State() *state.State

	// AgentConfig returns the agent config for the machine that is being
	// upgraded.
	AgentConfig() agent.Config
}

Context is used give the upgrade steps attributes needed to do their job.

func NewContext

func NewContext(agentConfig agent.Config, api *api.State, st *state.State) Context

NewContext returns a new upgrade context.

type Operation

type Operation interface {
	// The Juju version for which this operation is applicable.
	// Upgrade operations designed for versions of Juju earlier
	// than we are upgrading from are not run since such steps would
	// already have been used to get to the version we are running now.
	TargetVersion() version.Number

	// Steps to perform during an upgrade.
	Steps() []Step
}

Operation defines what steps to perform to upgrade to a target version.

type Step

type Step interface {
	// Description is a human readable description of what the upgrade step does.
	Description() string

	// Targets returns the target machine types for which the upgrade step is applicable.
	Targets() []Target

	// Run executes the upgrade business logic.
	Run(context Context) error
}

Step defines an idempotent operation that is run to perform a specific upgrade step.

type Target

type Target string

Target defines the type of machine for which a particular upgrade step can be run.