Stack

A stack is the blueprint for an application.

It defines which services the app uses and the default configuration for those services. To create an app, you choose a stack first.

All app instances of the same app share the same stack, but they can run different stack revisions.

Stacks are versioned. Every change creates a new stack revision.

The usual model is one stack per application. In some cases, multiple small similar apps may share a stack, but separate stacks are easier to evolve safely over time.

Creating Stacks

You can create a stack in three ways:

• Add a stack from the catalog, then customize it. Catalog stacks start from a curated stack definition and keep an origin, so you can later sync catalog-side changes into your customized stack.
• Create a new stack from scratch. Use this when you want to choose services and defaults yourself in the dashboard instead of starting from a catalog stack.
• Import a stack from a Git repository. The repository defines one or more custom stacks using a stack template, with each stack described by stack.yml and optional multi-stack index.yml.

After creation, all three paths produce regular versioned stacks. You can adjust their configuration, add or remove stack services, and create apps from any available revision.

flowchart TD
    subgraph APP["<div style='margin-top:10px; white-space: nowrap;'>App Instance (e.g. production)</div>"]
        subgraph sapp[ ]
            direction LR
            app1["app service"]
            app2["app service"]
            appEllipsis["..."]
            app3["app service"]
        end
        style sapp fill:none,stroke:none,stroke-width:0px
    end

    subgraph SR["<div style='margin-top:10px; white-space: nowrap;'>Stack Revision</div>"]
        subgraph sstack[ ]
            direction LR
            stack1["stack service"]
            stack2["stack service"]
            stackEllipsis["..."]
            stack3["stack service"]
        end
        style sstack fill:none,stroke:none,stroke-width:0px
    end

    subgraph sr[ ]
        direction LR
        svc1["service revision"] 
        svc2["service revision"] 
        svcEllipsis["..."]
        svc3["service revision"]
    end
    style sr fill:none,stroke:none,stroke-width:0px

    app1 -.-> stack1
    app2 -.-> stack2
    app3 -.-> stack3

    stack1 -.-> svc1
    stack2 -.-> svc2
    stack3 -.-> svc3

    APP --> SR

    classDef serviceRevision fill:#f0f0ff,stroke:#9370db,stroke-width:1px
    classDef stackRevision fill:#e6f0e6,stroke:#5c6bc0,stroke-width:2px
    classDef stackService fill:#f5f7ff,stroke:#8c9eff,stroke-width:1px
    classDef appInstance fill:#ffffff,stroke:#424242,stroke-width:1px
    classDef appService fill:#ffffff,stroke:#424242,stroke-width:1px
    classDef ellipsis fill:none,stroke:none

    class svc1,svc2,svc3 serviceRevision
    class SR stackRevision
    class stack1,stack2,stack3 stackService
    class APP appInstance
    class app1,app2,app3 appService
    class stackEllipsis,appEllipsis,svcEllipsis ellipsis

Updates

When a service used by the stack gets a new revision, or when stack-level configuration changes, the stack can become outdated and a new stack revision can be created.

Updating a stack does not automatically update all app instances using it. Each app instance can be upgraded to the latest stack revision separately.

If a stack was created from a catalog entry, it has an origin. You can sync it with that origin to pull catalog-side changes such as new services or new stack-wide defaults.

Sharing

A stack can be project-owned or organization-owned. Sharing makes the stack visible and usable in additional projects. A Modify/Delete share marks the project-stack link as write-capable where supported, without changing the owner.

See Sharing and Access control for the full ownership and permission model.