Some functions for managing instances will have to be used by new upcoming
unit tests, so they are taken out of the instances QA file and put in a new
utilities file accessible by other QA files as well.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Enable the monitoring daemon to invoke the Xen instance status data collector.
Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

The monitoring daemon needs to be able to run some commands that require root
access (such as "xm") in order to fulfill its duties.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

It will need to be accessed by the monitoring daemon.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Add a section related to the new collector.

Also, fix some formatting issue (white spaces, line longer than 80 chars)
in the DRBD collector section.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

The global status is computed from the statuses of the single instances.

The output json format is adapted to include this piece of information, as
prescribed by the design document.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

It will be used by multiple data collectors, not only the DRBD collector.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

The name of the list of instances was not specified.

Also, fix a line that was longer than 80 characters.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Instead of manually specify the name of the data collectors in mon-collector,
just use the dcName field each of them exports.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Instead of building the report as part of the "Main" function, have it
built by its own dedicated function, so that it will be able to export it
directly to the monitoring daemon when needed.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Name, version, format version, category and kind of the Instance Status data
collector are now exported.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Fetch the reason trail from file, failing gracefully if it is not found, and
include it in the output of the instance status data collector.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Added function for determining whether the status of an instance is ok, and to
represent this information in the corresponding field in the report.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Compute the actual state of the instance and export it.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Add the Xen instance status data collector with only its core features.
The next commits will add more reporting functionalities.

The access to the collector is made possible through the mon-collector
tool.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

The Xen instance status data collector will require to get some information
from the hypervisor. This commit introduces a module providing such functions.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Thomas Thrainer <thomasth@google.com>

The getInstReasonFilename is built to resemble the python corresponding
function.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

The tests are already using this library, so it's not really a new build
dependency, but it was not specified esplicitly.

Furthermore, it's going to be used by the instance status collector, so it's
added to the requirements for the monitoring subsystem.

Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

While this use case was described in the design document, and
mentioned several times as motivation for changes in commit messages,
it has never been added to a user-facing documentation. This commit
adds at least an example to the man page.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

While the multiple-tags test was added to verify that coloring is done
only after node selection (otherwise it wouldn't be possible to get in
both cases a single reboot group), it can easily be extended to also
verify that the correct nodes are selected by --node-tags.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

In the example configuration, the graph constructed by just connecting
primary and secondary instances is two-colorable. However, when taking
conflicting locations of secondary nodes into account, three reboot
groups are needed. Moreover, these reboot groups are not subordinated
to any two-coloring of the first-mentioned graph.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Thomas Thrainer <thomasth@google.com>

Make hroller take into account the nodes (redundant) instances
will be migrated to. This be behavior can be overridden by the
--offline-maintenance option which will make hroller plan under
the assumption that all instances will be shutdown before starting
with the rolling reboots.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Thomas Thrainer <thomasth@google.com>

For online rolling reboots, there are two kind of restrictions. First,
we cannot reboot the primary and secondary nodes of an instance
together. Secondly, two nodes cannot be rebooted simultaneously, if
they are the primary nodes of two instances with the same secondary
node. The second condition requires knowledge of all nodes, not only
those the graph is to be constructed on.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Thomas Thrainer <thomasth@google.com>

Add a new option to hroller to only output information about the first
reboot group. Together with the option --node-tags this allows for the
following work flow. First tag all nodes; then repeatedly compute the
first node group, handle these nodes and remove the tags. In between
these steps, other operations can be carried out on the cluster.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Thomas Thrainer <thomasth@google.com>

Make hroller output the node groups not containing the master node
sorted by size, largest group first. The master node still remains
the last node of the last reboot group. In this way, most progress
is made when switching back to normal cluster operations after the
first reboot group.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Thomas Thrainer <thomasth@google.com>

Regular expressions are not shell globs. So "any symbol" is expressed
by a dot, not a question mark. In this case, the confusion lead to a
too liberal expectation, hence the test passed. Fix it nevertheless.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

The order of evaluation of the conditions is changed, so it's easier to add
more (foreseen) checks for exclusive_storage.

Signed-off-by: Bernardo Dal Seno <bdalseno@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Prereq checks relative disks are grouped together and moved in a separate
method. This reduces the clutter in CheckPrereq().

Signed-off-by: Bernardo Dal Seno <bdalseno@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

The example is a cluster of 6 nodes, paired into 3 group by three
instances. So the whole cluster would need two reboot groups. The two
tags select, in two different ways, one node of each group. So, when
restricting to one tag, a single reboot group suffices, but no
coloring of the whole cluster would achieve this.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

Add option --node-tags to tell hroller to consider only nodes
with these tags. A use case would be a tag tracking on which
nodes the maintenance has not yet been carried out, e.g., if
rolling reboots are interleaved with other cluster operations.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

Since the htools representation of a node now allows adding
the node tags, populate this field correctly in the Rapi
backend.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

Since the htools representation of a node now allows adding
the node tags, populate this field correctly in the LUXI
backend.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

In order to allow htools to make use of node tags, add them to the
text format. This is done by adding a new column at the end of the
node lines. If this column is missing, the default value (which
is the empty list) is left unchanged, thus yielding the current
behavior.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

Since hroller (and probably other tools in the future) will support
node selection based on node tags, extend the node data structure to
allow adding this information.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

Hroller used to first compute a coloring of the node graph and then
filter out the nodes that it had to work on. While the only filtering
was according to node groups this did not make a difference, as there
shouldn't be any instance with primary and secondary node on different
node groups. With more elaborate filtering, however, reducing the graph
first can lead to better reboot groups.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

Change the behavior of mkNodeGraph to tacitly ignore all instances
where one of the nodes is not in the list of nodes. In this way, we
can construct sub-graphs by filtering the nodes and ignoring any
possibly added isolated nodes for the missing indexes.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

In hroller, the option -O can be used to mark certain nodes as offline.
These nodes should then not be part of any reboot group. Add tests
to verify this behavior.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

In commit 7dbe4c72 the new option --force was introduced to
hroller. Change the man page to reflect this change.

Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

Mention the main features of DRBD 8.4 support in the NEWS file.

Signed-off-by: Thomas Thrainer <thomasth@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>