Most of these actions/conditionals were looking for primary state, but
were failing during node takeover. Update the conditionals to look for
both router states instead.
Also add a wait to lock flushing until a takeover is completed.
Use a pair of transitional states, "takeover" and "relinquish", when
transitioning between primary and secondary coordinator states. This
provides a clsuter-wide record that the nodes are still working during
their synchronous transition states, and should allow clients to
determine when the node(s) have fully switched over. Also add an
additional 2 seconds of wait at the end of the transition jobs to ensure
everything has had a chance to start before proceeding.
References #72
Rename "pvcd" to "pvcnoded", and "pvc-api" to "pvcapid" so names for the
daemons are fully consistent. Update the names of the configuration
files as well to match this new formatting.
References #79
Modifies the storage and upstream networks to mirror the cluster
network, with a bridge on top of the underlying specified dev, and all
IPs bound to the bridge.
Allows creating VMs in the storage or upstream networks, as well as the
cluster network, should the administrator choose to do so (manually).
Implements a "maintenance mode" for PVC clusters. For now, the only
thing this mode does is disable node fencing while the state is true.
This allows the administrator to tell PVC that network connectivity,
etc. might be interrupted and to avoid fencing nodes.
Closes#70
Required due to #64. Bridged networks were being created on top of a
vLAN if the Cluster network was a vLAN device, rather than being created
on the underlying device. This came from a previous revision of the
cluster architecture guidelines where Cluster was supposed to be a raw
device rather than a vLAN. This fixed the problem by implementing a
configuration field for a "bridge_device", a NIC device that can then
have the bridged vLANs created on top of it.
Fixes#64
Prevents blocking the main thread(s) while a VM is changing state. In
particular, this caused some issues with nodes not responding to
cancellation/reversal of a flush/ready state until the previous
migration was finished, which could cause issues. This entire subset of
actions is now threaded and so can run on its own in the background.
This particular arping interval/count, along with forcing it to run in
the foreground, seems to minimize the packet loss when the primary
coordinator transitions. Through extensive testing, this value results
in the, consistently, least amount of loss: 1-2 pings, at an 0.025s ping
interval, return "TTL exceeded", with no other loss, and only when the
node the test VM is on is the one switching to secondary state. No other
combination of values here, nor tweaks to other parts of the code, seem
able to reduce this further, therefore this is likely the best
configuration possible.
The previous method was a "throw it in the sea"-type migration with some
(very arbitrary) sleep statements thrown in for good measure.
Reimplement this with some hard locking. During each phase of the
transition, the nodes acquire read/write shared locks to a Zookeeper key
so that they can tightly coordinate the actions of transferring each
part of the primary state between them. This is done in a subthread to
prevent strange blocking issues that were encountered, likely due to
business in the existing main thread.
Joshua Boniface