container.training/slides/k8s/versions-k8s.md at gitpod

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Jerome Petazzoni 454843b755 Bump up versions

2020-04-02 07:39:10 -05:00

Versions installed

.exercise[

Check all installed versions:

kubectl version
docker version
docker-compose -v

]

class: extra-details

Kubernetes 1.17 validates Docker Engine version up to 19.03

however ...
Kubernetes 1.15 validates Docker Engine versions up to 18.09
(the latest version when Kubernetes 1.14 was released)
Kubernetes 1.13 only validates Docker Engine versions up to 18.06
Is it a problem if I use Kubernetes with a "too recent" Docker Engine?

class: extra-details

No!
"Validates" = continuous integration builds with very extensive (and expensive) testing
The Docker API is versioned, and offers strong backward-compatibility
(if a client uses e.g. API v1.25, the Docker Engine will keep behaving the same way)

Kubernetes versions are expressed using semantic versioning

(a Kubernetes version is expressed as MAJOR.MINOR.PATCH)
There is a new patch release whenever needed

(generally, there is about 2 to 4 weeks between patch releases, except when a critical bug or vulnerability is found: in that case, a patch release will follow as fast as possible)
There is a new minor release approximately every 3 months
At any given time, 3 minor releases are maintained

(in other words, a given minor release is maintained about 9 months)

Should my version of kubectl match exactly my cluster version?

kubectl can be up to one minor version older or newer than the cluster

(if cluster version is 1.15.X, kubectl can be 1.14.Y, 1.15.Y, or 1.16.Y)
Things might work with larger version differences

(but they will probably fail randomly, so be careful)

This is an example of an error indicating version compability issues:

error: SchemaError(io.k8s.api.autoscaling.v2beta1.ExternalMetricStatus):
invalid object doesn't have additional properties