spec, libcni: add cniVersions field in CNI configurations #1010
Conversation
|
In retrospect, I think we do want this. It will make auto-generating CNI configuration file versions easier. If a cluster is in the midst of changing container runtimes (e.g updating CRI-O), then it may not be possible for an administrator to easily determine the CNI version in use. Allowing for multiple versions simplifies the rollout strategy. |
SPEC.md
Outdated
| @@ -185,6 +188,15 @@ Plugins may define additional fields that they accept and may generate an error | |||
| } | |||
| ``` | |||
|
|
|||
| ### Version considerations | |||
|
|
|||
| CNI runtimes and plugins may support multiple versions of the protocol. To indicate that a particular configuration supports | |||
There was a problem hiding this comment.
@squeed maybe "CNI runtimes, plugins, and configurations may each support multiple versions of the CNI specification independently. Plugins indicate supported CNI specification versions through the reply to the VERSION command, while network configurations may indicate multiple supported CNI specification versions through the cniVersions field.
Runtimes are thus able to query both plugins and configurations and select a commonly supported CNI specification version for the CNI request. The runtime MUST select the highest supplied version that it supports. If both cniVersion and cniVersions are supplied, the runtime MUST select the highest of the two.
This adds a new top-level configuration field, `cniVersions`, where network configurations can indicate support for more than one version. This is to enable easy upgrading of CNI versions in plugins without lock-step updates to the runtime. Signed-off-by: Casey Callendrello <c1@caseyc.net>
Signed-off-by: Casey Callendrello <c1@caseyc.net>
libcni/conf.go
Outdated
| } | ||
| } | ||
| sort.Sort(semver.Collection(vs)) | ||
| cniVersion = vs[len(vs)-1].String() |
There was a problem hiding this comment.
@squeed What if vs is empty? eg if somebody writes cniVersions: [], or whatever it is in JSON
This implements the `cniVersions` field in the network configuration list. It allows for CNI plugins to specify that they support multiple versions, and the runtime may select the highest version it supports. Signed-off-by: Casey Callendrello <c1@caseyc.net>
As outlined in #941, it would be useful to CNI vendors to specify that they support multiple versions. This PR provides the spec and libcni implementation of that feature.
Specifically, it allows writing config lists like
for which libcni would select version 1.1.0 when calling the plugins.