sigs.k8s.io/cluster-api@v1.7.1/docs/community/20231016-in-place-upgrades.md (about)

     1  ---
     2  title: Feature Group for In-place Upgrades support in Cluster API
     3  authors:
     4    - "@g-gaston"
     5  reviewers:
     6      - "@dharmjit"
     7      - "@vincepri"
     8      - "@sbueringer"
     9      - "@fabriziopandini"
    10  creation-date: 2023-10-16
    11  last-updated: 2023-10-16
    12  status: proposed
    13  see-also:
    14    - https://github.com/kubernetes-sigs/cluster-api/issues/9489
    15    - https://docs.google.com/document/d/1CqQ1SAqJD264PsDeMj_Z3HhZxe7DViNkpJ9d5q-2Zck
    16  ---
    17  # In-place upgrades Feature Group
    18  
    19  This document briefly outlines the scope, communication media, and stakeholders for a formal Feature Group dedicated to defining a Cluster API-approved solution to upgrade the kubernetes components running in CAPI managed nodes without replacing those machines.
    20  
    21  ## User Story and Problem Statement
    22  
    23  As a CAPI Kubernetes cluster admin I want to upgrade the k8s components (for example, a minor Kubernetes upgrade) of my cluster without replacing the machines.
    24  
    25  At present, CAPI has "immutable infrastructure" as one of its axioms: once created, Machines are not updated, they are just replaced (a new one is created and old one is deleted). As a consequence, the only supported upgrade strategy is rolling update. However, for certain use cases (such as Single-Node Clusters with no spare capacity, Multi-Node Clusters with VM/OS customizations for high-performance/low-latency workloads or dependency on local persistent storage), upgrading a cluster via RollingUpdate strategy could either be not feasible or a costly operation (requiring to re-apply customizations on newer nodes and hence more downtime).
    26  
    27  ## Scope
    28  
    29  The scope of this effort will be the following:
    30  
    31  1. Define the scope of what In-place upgrades means in the context of Cluster API.
    32  2. Write a CAPI proposal with the recommended solution.
    33  
    34  ## Communication
    35  
    36  We will meet on [Wednesdays at 08:00 PT (Pacific Time)][zoomMeeting]. [Convert to your timezone](https://dateful.com/time-zone-converter?t=09:00&tz=PT%20%28Pacific%20Time%29). Meeting notes will be documented in this [Google Doc](https://docs.google.com/document/d/1GmRd6MyQ0mWAoJV6rCHhZTSTtKMKHdJzhXm0BLBXOnw).
    37  
    38  Regular, summarized updates of group progress will be provided during weekly Cluster API office hours on Wednesdays @ 10:00 PT on [Zoom][zoomMeeting].
    39  
    40  Chat with stakeholders on Kubernetes [Slack](http://slack.k8s.io/) in the [cluster-api](https://kubernetes.slack.com/archives/C8TSNPY4T) channel.
    41  
    42  ## Stakeholders
    43  
    44  Primary Stakeholders are listed below:
    45  
    46  - Mayur Das (@mayur-tolexo, VMware)
    47  - Alexander Demicev (@alexander-demicev, SUSE)
    48  - Scott Dodson (@sdodson, Red Hat)
    49  - Guillermo Gaston (@g-gaston, AWS)
    50  - Furkat Gofurov (@furkatgofurov7, SUSE)
    51  - Dharmjit Singh (@dharmjit, VMware)
    52  
    53  [zoomMeeting]: https://zoom.us/j/861487554