The new CA framework introduced basic support for comma-separated
list of management servers for agent, which makes an external LB
unnecessary.
This extends that feature to implement LB sorting algorithms that
sorts the management server list before they are sent to the agents.
This adds a central intelligence in the management server and adds
additional enhancements to Agent class to be algorithm aware and
have a background mechanism to check/fallback to preferred management
server (assumed as the first in the list). This is support for any
indirect agent such as the KVM, CPVM and SSVM agent, and would
provide support for management server host migration during upgrade
(when instead of in-place, new hosts are used to setup new mgmt server).
This FR introduces two new global settings:
- `indirect.agent.lb.algorithm`: The algorithm for the indirect agent LB.
- `indirect.agent.lb.check.interval`: The preferred host check interval
for the agent's background task that checks and switches to agent's
preferred host.
The indirect.agent.lb.algorithm supports following algorithm options:
- static: use the list as provided.
- roundrobin: evenly spreads hosts across management servers based on
host's id.
- shuffle: (pseudo) randomly sorts the list (not recommended for production).
Any changes to the global settings - `indirect.agent.lb.algorithm` and
`host` does not require restarting of the mangement server(s) and the
agents. A message bus based system dynamically reacts to change in these
global settings and propagates them to all connected agents.
Comma-separated management server list is propagated to agents on
following cases:
- Addition of a host (including ssvm, cpvm systevms).
- Connection or reconnection by the agents to a management server.
- After admin changes the 'host' and/or the
'indirect.agent.lb.algorithm' global settings.
On the agent side, the 'host' setting is saved in its properties file as:
`host=<comma separated addresses>@<algorithm name>`.
First the agent connects to the management server and sends its current
management server list, which is compared by the management server and
in case of failure a new/update list is sent for the agent to persist.
From the agent's perspective, the first address in the propagated list
will be considered the preferred host. A new background task can be
activated by configuring the `indirect.agent.lb.check.interval` which is
a cluster level global setting from CloudStack and admins can also
override this by configuring the 'host.lb.check.interval' in the
`agent.properties` file.
Every time agent gets a ms-host list and the algorithm, the host specific
background check interval is also sent and it dynamically reconfigures
the background task without need to restart agents.
Note: The 'static' and 'roundrobin' algorithms, strictly checks for the
order as expected by them, however, the 'shuffle' algorithm just checks
for content and not the order of the comma separate ms host addresses.
Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
Commit enables a new feature for KVM hypervisor which purpose is to increase virtually amount of RAM available beyond the actual limit.
There is a new parameter in agent.properties: host.overcommit.mem.mb which enables adding specified amount of RAM to actually available. It is necessary to utilize KSM and ZSwap features which extend RAM with deduplication and compression.
The watchdog timer adds functionality where the Hypervisor can detect if an
instance has crashed or stopped functioning.
The watchdog timer adds functionality where the Hypervisor can detect if an
instance has crashed or stopped functioning.
When the Instance has the 'watchdog' daemon running it will send heartbeats
to the /dev/watchdog device.
If these heartbeats are no longer received by the HV it will reset the Instance.
If the Instance never sends the heartbeats the HV does not take action. It only
takes action if it stops sending heartbeats.
This is supported since Libvirt 0.7.3 and can be defined in the XML format as
described in the docs: https://libvirt.org/formatdomain.html#elementsWatchdog
To the 'devices' section this will be added:
In the agent.properties the action to be taken can be defined:
vm.watchdog.action=reset
The same goes for the model. The Intel i6300esb is however the most commonly used.
vm.watchdog.model=i6300esb
When the Instance has the 'watchdog' daemon running it will send heartbeats
to the /dev/watchdog device.
If these heartbeats are no longer received by the HV it will reset the Instance.
If the Instance never sends the heartbeats the HV does not take action. It only
takes action if it stops sending heartbeats.
This is supported since Libvirt 0.7.3 and can be defined in the XML format as
described in the docs: https://libvirt.org/formatdomain.html#elementsWatchdog
To the 'devices' section this will be added:
<watchdog model='i6300esb' action='reset'/>
In the agent.properties the action to be taken can be defined:
vm.watchdog.action=reset
The same goes for the model. The Intel i6300esb is however the most commonly used.
vm.watchdog.model=i6300esb
Signed-off-by: Wido den Hollander <wido@widodh.nl>
This commit adds a additional VirtIO channel with the name
'org.qemu.guest_agent.0' to all Instances.
With the Qemu Guest Agent the Hypervisor gains more control over the Instance if
these tools are present inside the Instance, for example:
* Power control
* Flushing filesystems
* Fetching Network information
In the future this should allow safer snapshots on KVM since we can instruct the
Instance to flush the filesystems prior to snapshotting the disk.
More information: http://wiki.qemu.org/Features/QAPI/GuestAgent
Keep in mind that on Ubuntu AppArmor still needs to be disabled since the default
AppArmor profile doesn't allow libvirt to write into /var/lib/libvirt/qemu
This commit does not add any communication methods through API-calls, it merely
adds the channel to the Instances and installs the Guest Agent in the SSVMs.
With the addition of the Qemu Guest Agent channel a second channel appears in /dev
on a SSVM as a VirtIO port.
The order in which the ports are defined in the XML matters for the naming inside
the SSVM VM and by not relying on /dev/vportXX but looking for a static name the
SSVM still boots properly if the order in the XML definition is changed.
A SSVM with both ports attached will have something like this:
root@v-215-VM:~# ls -l /dev/virtio-ports
total 0
lrwxrwxrwx 1 root root 11 May 13 21:41 org.qemu.guest_agent.0 -> ../vport0p2
lrwxrwxrwx 1 root root 11 May 13 21:41 v-215-VM.vport -> ../vport0p1
root@v-215-VM:~# ls -l /dev/vport*
crw------- 1 root root 251, 1 May 13 21:41 /dev/vport0p1
crw------- 1 root root 251, 2 May 13 21:41 /dev/vport0p2
root@v-215-VM:~#
In this case the SSVM port points to /dev/vport0p1, but if the order in the XML
is different it might point to /dev/vport0p2
By looking for a portname with a pre-defined pattern in /dev/virtio-ports we
do not rely on the order in the XML definition.
Signed-off-by: Wido den Hollander <wido@widodh.nl>
By adding a Random Number Generator device to Instances we can prevent
entropy starvation inside guest.
The default source is /dev/random on the host, but this can be configured
to another source when present, for example a hardware RNG.
When enabled it will add the following to the Instance's XML definition:
<rng model='virtio'>
<rate period='1000' bytes='2048' />
<backend model='random'>/dev/random</backend>
</rng>
If the Instance has the proper support, which most modern distributions have,
it will have a /dev/hwrng device which it can use for gathering entropy.
More information: https://libvirt.org/formatdomain.html#elementsRng
Implements a VM volume/disk file activity checker that checks if QCOW2 file
has been changed before starting the VM. This is useful as a pessimistic
approach to save VMs that were running on faulty hosts that CloudStack could
try to launch on other hosts while the host was not cleanly fenced. This is
optional and available only if you enable the settings in agent.properties
file, on per-host basis.
Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
This improvements checks for "guest.cpu.features" property which is a space
separated list of cpu features that is specific for a host. When added, it
will add <feature policy='require' name='{{feature-you-listed}}'/> in the
<cpu> section of the generated vm spec xml.
Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
(cherry picked from commit ea7fd37783cbc7ec78de5a5e84395381b1800a3e)
Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
Detail: lack of newline at end of file was keeping cloudstack-setup-agent from
properly editing/creating new config.
BUG-ID: CLOUDSTACK-1487
Signed-off-by: Marcus Sorensen <marcus@betterservers.com> 1362191198 -0700
