forked from openebs/lvm-localpv
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
feat(lvm-driver): enable RAID support
Add support for LVM2 RAID types and parameters, with sane defaults for backwards compatibility. lvm-driver now assumes that a non- specified RAID type corresponds to the previous default of linear RAID, where data is packed onto disk until it runs out of space, continuing to the next as necessary. Tests have been added to cover the main supported RAID types (e.g. raid0, raid1, raid5, raid6, and raid10), but technically any valid LVM RAID type should work as well. Fixes openebs#164 Signed-off-by: Nicholas Cioli <[email protected]>
- Loading branch information
1 parent
9e0ac5b
commit 32dec67
Showing
15 changed files
with
648 additions
and
2 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1 @@ | ||
| add support for LVM raid options |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,129 @@ | ||
| --- | ||
| title: LVM-LocalPV RAID | ||
| authors: | ||
| - "@nicholascioli" | ||
| owners: [] | ||
| creation-date: 2023-11-04 | ||
| last-updated: 2023-11-04 | ||
| status: Implemented | ||
| --- | ||
|
|
||
| # LVM-LocalPV RAID | ||
|
|
||
| ## Table of Contents | ||
| - [LVM-LocalPV RAID](#lvm-localpv-raid) | ||
| - [Table of Contents](#table-of-contents) | ||
| - [Summary](#summary) | ||
| - [Motivation](#motivation) | ||
| - [Goals](#goals) | ||
| - [Non Goals](#non-goals) | ||
| - [Proposal](#proposal) | ||
| - [User Stories](#user-stories) | ||
| - [Implementation Details](#implementation-details) | ||
| - [Usage details](#usage-details) | ||
| - [Test Plan](#test-plan) | ||
| - [Graduation Criteria](#graduation-criteria) | ||
| - [Drawbacks](#drawbacks) | ||
| - [Alternatives](#alternatives) | ||
|
|
||
|
|
||
| ## Summary | ||
|
|
||
| This proposal charts out the workflow details to support creation of RAID volumes. | ||
|
|
||
| ## Motivation | ||
|
|
||
| ### Goals | ||
|
|
||
| - Able to provision RAID volumes in a VolumeGroup. | ||
| - Able to specify VolumeGroup-specific RAID options for all sub volumes. | ||
| - Able to specify extra options for all volumes in a VolumeGroup. | ||
|
|
||
| ### Non Goals | ||
|
|
||
| - Validating combinations of RAID types / options. | ||
|
|
||
| ## Proposal | ||
|
|
||
| ### User Stories | ||
|
|
||
| - RAIDed volumes provide data redundancy and can mitigate data loss due to individual drive failures. | ||
| - Ability to specify extra arguments for VolumeGroups allow for user customizations without needing | ||
| to rework k8s schemas. | ||
|
|
||
| ### Implementation Details | ||
|
|
||
| - User/Admin has to set RAID-sepcific options under storageclass parameters which | ||
| are used when creating volumes in the VolumeGroup. | ||
| - During volume provisioning time external-provisioner will read all key-value pairs | ||
| that are specified under referenced storageclass and pass information to CSI | ||
| driver as payload for `CreateVolume` gRPC request. | ||
| - After receiving the `CreateVolume` request CSI driver will pick appropriate node based | ||
| on scheduling attributes(like topology information, matching VG name and available capacity) | ||
| and creates LVM volume resource by setting `Spec.RaidType` to a valid type along with other properties. | ||
| - Once the LVMVolume resource is created corresponding node LVM volume controller reconcile | ||
| LVM volume resource in the following way: | ||
| - LVM controller will check `Spec.RaidType` field, if the field is set to anything other | ||
| than `linear`, then the controller will perform following operations: | ||
| - Fetch information about existence of matching VolumeGroup. | ||
| - If there is a VolumeGroup with <vg_name> name then controller will create a volume. | ||
| Command used to create thin volume: `lvcreate --type <RAID_TYPE> --raidintegrity <INTEGRITY> --nosync ... <LVCREATEOPTIONS> -y` | ||
| - If volume creation is successfull then controller will LVM volume resource as `Ready`. | ||
| - After watching `Ready` status CSI driver will return success response to `CreateVolume` gRPC | ||
| request. | ||
|
|
||
| ### Usage details | ||
|
|
||
| 1. User/Admin can configure the following options under the storageclass parameters. | ||
|
|
||
| Option | Required | Valid Values | Description | ||
| -------|----------|--------------|------------------- | ||
| `type` | `true` | `raid0` / `stripe`, `raid` / `raid1` / `mirror`, `raid5`, `raid6`, `raid10` | The RAID type of the volume. | ||
| `integrity` | `false` | `true`, `false` | Whether or not to enable DM integrity for the volume. Defaults to `false`. | ||
| `mirrors` | depends | [0, ∞) | Mirror count. Certain RAID configurations require this to be set. | ||
| `nosync` | `false` | `true`, `false` | Whether or not to disable the initial sync. Defaults to false. | ||
| `stripecount` | depends | [0, ∞) | Stripe count. Certain RAID configurations require this to be set. | ||
| `stripesize` | `false` | [0, ∞) (but must be a power of 2) | The size of each stripe. If not specified, LVM will choose a sane default. | ||
| `lvcreateoptions` | `false` | String, delimited by `;` | Extra options to be passed to LVM when creating volumes. | ||
|
|
||
| An example is shown below | ||
| ```yaml | ||
| apiVersion: storage.k8s.io/v1 | ||
| kind: StorageClass | ||
| metadata: | ||
| name: openebs-lvm | ||
| provisioner: local.csi.openebs.io | ||
| parameters: | ||
| storage: "lvm" | ||
| volgroup: "lvmvg" | ||
| raidType: "raid1" | ||
| lvcreateoptions: "--vdo;--readahead auto" | ||
| ``` | ||
| ### Test Plan | ||
| - Provision an application on various RAID configurations, verify volume accessibility from application, | ||
| and verify that `lvs` reports correct RAID information. | ||
|
|
||
| ## Graduation Criteria | ||
|
|
||
| All testcases mentioned in [Test Plan](#test-plan) section need to be automated | ||
|
|
||
| ## Drawbacks | ||
|
|
||
| - Since the RAID options exist at the storageclass level, changes to the storage | ||
| class RAID options is not possible without custom logic per RAID type or manual | ||
| operator interactions. | ||
| - Validation of the RAID options depend on the version of LVM2 installed as well as | ||
| the type of RAID used and its options. This is outside of the scope of these changes | ||
| and will cause users to have to debug issues with a finer comb to see why certain | ||
| options do not work together or on their specific machine. | ||
|
|
||
| ## Alternatives | ||
|
|
||
| RAID can be done in either software or hardware, with many off-the-shelf products | ||
| including built-in hardware solutions. There are also other software RAID alternatives | ||
| that can be used below LVM, such as mdadm. | ||
|
|
||
| This unfortunately requires operators to decouple | ||
| the SotrageClass from the RAID configuration, but does simplify the amount of code maintained by | ||
| this project. |
Oops, something went wrong.