We adapt the existing code to work across all zones in a region.
We require a feature-flag to enable Ubernetes-Lite
Reasons:
* There are some behavioural changes if users create volumes with
the same name in two zones.
* We don't want to make one API call per zone if we're not running
Ubernetes-Lite.
* Ubernetes-Lite is still experimental.
There isn't a parallel flag implemented for AWS, because at the moment
there would be no behaviour changes from this.
This is for internal use at the moment, for testing Ubernetes Lite, but
arguably makes the code a little cleaner.
Also rename KUBE_SHARE_MASTER -> KUBE_USE_EXISTING_MASTER
Some functionality in hack/lib is currently depended on by
cluster/common.sh so kube-up from the full release tar (which
does not include hack/) is currently broken. With this PR we
create cluster/lib/ and move the necessary bits from hack/
over to get kube-up working again.
Fixes: 96d1b8d1b2
Signed-off-by: Mike Danese <mikedanese@google.com>
Implement a flag that defines the frequency at which a node's out of
disk condition can change its status. Use this flag to suspend out of
disk status changes in the time period specified by the flag, after
the status is changed once.
Set the flag to 0 in e2e tests so that we can predictably test out of
disk node condition.
Also, use util.Clock interface for all time related functionality in
the kubelet. Calling time functions in unversioned package or time
package such as unversioned.Now() or time.Now() makes it really hard
to test such code. It also makes the tests flaky and sometimes
unnecessarily slow due to time.Sleep() calls used to simulate the
time elapsed. So use util.Clock interface instead which can be faked
in the tests.
For AWS EBS, a volume can only be attached to a node in the same AZ.
The scheduler must therefore detect if a volume is being attached to a
pod, and ensure that the pod is scheduled on a node in the same AZ as
the volume.
So that the scheduler need not query the cloud provider every time, and
to support decoupled operation (e.g. bare metal) we tag the volume with
our placement labels. This is done automatically by means of an
admission controller on AWS when a PersistentVolume is created backed by
an EBS volume.
Support for tagging GCE PVs will follow.
Pods that specify a volume directly (i.e. without using a
PersistentVolumeClaim) will not currently be scheduled correctly (i.e.
they will be scheduled without zone-awareness).
