Refactoring Remus setup by introducing libxl__remus_setup API.
All Remus setup work are done in this function.
There is a subtle behavioural change here, which is that if anything
which is now done in _setup fails then the result is a call to
dss->callback( ..,..,ERROR_FAIL) rather than _start returning
AO_CREATE_FAIL(ERROR_FAIL). But this is correct and intended.
Also remove the libxl__ prefix for static functions.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
There are 2 remus checkpoint callbacks(save/restore), currently, they
both called libxl__remus_domain_checkpoint_callback in different
files, so it is ok. But in the following patch, we will move all of the
remus callback code into a separate file, the name should be different.
So rename them to:
libxl__remus_domain_{save/restore}_checkpoint_callback
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Move domain suspend code into a separate file libxl_dom_suspend.c.
Add an API libxl__domain_suspend() which wraps the static
function domain_suspend_callback_common() for internal use.
Export the existing API libxl__domain_suspend_callback() used by
libxc to suspend the guest during migration.
Note that the newly added file libxl_dom_suspend.c is used for
suspend/resume code.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
The suspend/save terminology used by libxc is more consistent.
"suspend" refers to quiescing the VM, so pausing qemu, making a
remote_shutdown(SHUTDOWN_suspend) hypercall etc.
"save" refers to the actions involved in actually shuffling the
state of the VM, so xc_domain_save() etc.
libxl currently uses "suspend" to encapsulate both. The patch
Rename libxl__domain_suspend() to libxl__domain_save() since it
actually refers to shuffling the state of the VM.
This results in some strangeness in that some functions called *save*
are now passed a struct called *suspend*, this is temporary and is all
fixed up later by the refactoring of the suspend_state.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Some comments, commit messages:
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Split read/handle qemu info. The receiving of qemu info
should be done while we receive the migration stream,
handle_qemu will be called when the stream complete.
Otherwise, it will break Remus because read_record()
won't read qemu info and stream_complete will be called
at failover.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
When we use a DECLARE_HYPERCALL_BUFFER_SHADOW it defines a user
pointer '_name' and a shadow xc_hypercall_buffer_t.
When calling xc_hypercall_buffer_free_pages(_xch, _name, _nr),
the complier will report '_name' unused error, because
xc_hypercall_buffer_free_pages() is a MACRO and '_name' is
transparently converted to the hypercall buffer. it confuses
the caller because xc_hypercall_buffer_free_pages() looks
like a function and takes '_name' as an arg.
Add an if check to let the compiler think we are actually
using the argument '_name'.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
[ ijc -- some rewording of the commit message ]
There are cases where we only need to use the hypercall buffer data,
and do not use the xc_hypercall_buffer_t struct.
DECLARE_HYPERCALL_BUFFER_SHADOW defines a user pointer that can allow
us to access the hypercall buffer data but it also defines a
xc_hypercall_buffer_t that we don't use, the compiler will report arg
unused error.
Add __attribute__((unused)) before xc_hypercall_buffer_t to avoid
the compiler error.
Example cases:
In send_all_pages(), we only need to use the hypercall buffer data
which is a dirty bitmap, we set the dirty bitmap to all dirty and call
send_dirty_pages, we will not use the xc_hypercall_buffer_t and hypercall
to retrieve the dirty bitmap.
In send_some_pages(), we will also only need to use the dirty_bitmap.
the retrieve dirty bitmap hypercall are done by the caller.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Disk replication is enabled by default. This patch adds a cmdline
switch to 'xl remus' command to explicitly disable disk replication.
A new boolean field 'diskbuf' is added to the libxl_domain_remus_info
structure to represent this configuration option inside libxl.
Note: Disabling disk replication requires enabling unsafe mode.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Add two members in libxl_domain_remus_info:
netbuf: whether netbuf is enabled
netbufscript: the path of the script which will be run to setup
and tear down the guest's interface.
Add cmdline switches to 'xl remus' command to enable or disable
network buffering and a domain-specific hotplug script to setup
network buffering.
Add a new config var 'remus.default.netbufscript' to xl.conf, that
allows the user to override the default global script used to
setup network buffering.
Note: Network buffering is enabled by default. Disabling network
buffering requires enabling unsafe mode.
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
By default, network buffering and disk replication are enabled;
checkpoints are replicated to another standby VM.
This patch allows the user to disable any of these features by
explicitly specifying a 'run in unsafe mode' switch when invoking
the 'xl remus' command. While running Remus in an unsafe mode
makes little sense under normal circumstances, it is useful to be
able to disable one or more features mentioned above for
testing/debugging/profiling purposes.
Unless this option is enabled, it will not be possible to
replicate memory checkpoints to /dev/null (blackhole replication),
disable network buffering or disk replication.
As a starter, the use of blackhole replication now requires that
the unsafe mode be enabled. Subsequent patches will add support
for disabling network buffering and disk replication in a similar
manner.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This patch adds the machinery required for protecting a guest's
disk state, when the guest disk uses a DRBD disk backend.
This patch comprises of two parts:
1. Hotplug scripts: The block-drbd-probe script is responsible for
performing sanity checks on the state of the DRBD disk before the
checkpointing process begins. This script should be invoked by
libxl for each of the guest's disk devices, when starting Remus.
2. Remus drbd disk device: Implements the interfaces required by the
remus abstract device layer. A note about the implementation:
a) setup() is called for each disk attached to the guest.
During setup():
i) The hotplug script is called to perform the sanity check.
ii) Libxl obtains a handle to the DRBD device (/dev/drbd*) and
and subsequently controls disk checkpoint replication using
this handle in the checkpoint callbacks.
c) The preresume() checkpoint callback is executed asynchronously
using libxl__ev_child_fork(), as it may potentially block for more
than few seconds in case of backup failure.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This patch adds the machinery required for protecting a guest's
network device state. This patch comprises of two parts:
1. Hotplug scripts: The remus-netbuf-setup script is responsible for
setting up and tearing down the necessary infrastructure required for
network output buffering. This script should be invoked by libxl for
each of the guest's network interfaces, when starting or stopping Remus.
Apart from returning success/failure indication via the usual hotplug
entries in xenstore, this script also writes to xenstore, the name of
the REMUS_IFB device to be used to control the vif's network output.
The script relies on libnl3 command line utilities to perform various
setup/teardown functions. The script is confined to Linux platforms only
since NetBSD does not seem to have libnl3.
2. Remus network device: Implements the interfaces required by the
remus abstract device layer. A note about the implementation:
a) init_subkind_nic() & cleanup_subkind_nic() are called once per Remus
invocation. They establish and free netlink related state respectively.
b) setup() and teardown are called for each vif attached to the
guest.
During setup():
i) The hotplug script is called to setup a network buffer on a
given vif. The script chooses an available IFB device from
the system, redirects vif egress traffic to the IFB device
and sets up the plug qdisc (output buffer) on the IFB device.
The name of the IFB device is communicated via xenstore to
libxl.
ii) Libxl obtains a handle to the plug qdisc using the libnl3 API
and subsequently controls output buffering using this handle
in the checkpoint callbacks.
During teardown(), the hotplug scripts are called again to remove
the vif->ifb traffic redirection, release the ifb and the plug
qdisc associated with it.
c) The checkpoint callbacks [postsuspend(), preresume() and commit()]
are implemented as synchronous ops as the netlink calls associated
with the qdisc subsystem are very fast.
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Introduce an abstract device layer that allows the Remus
logic in libxl to control a guest's devices in a device-agnostic
manner. The device layer also exposes a set of internal interfaces
that a device type must implement, if it wishes to support Remus.
The following API are exposed to libxl:
One-time configuration operations:
*libxl__remus_devices_setup
> Enable output buffering for NICs, setup disk replication, etc.
*libxl__remus_devices_teardown
> Disable network output buffering and disk replication;
teardown any associated external setups like qdiscs for NICs.
Operations executed every checkpoint (in order of invocation):
*libxl__remus_devices_postsuspend
*libxl__remus_devices_preresume
*libxl__remus_devices_commit
Each device type needs to implement the interfaces specified in
the libxl__remus_device_instance_ops if it wishes to support Remus.
The high-level control flow through the Remus device layer is shown below:
xl remus
|-> libxl_domain_remus_start
|-> libxl__remus_devices_setup
|-> Per-checkpoint libxl__remus_devices_[postsuspend,preresume,commit]
...
|-> On backup failure/network error/other errors
libxl__remus_devices_teardown
callback processing
* Only call the per-device libxl__multidev_one_callback
when the iteration has succeded or failed.
* The final callback (called by multidev) is a trivial
shim to shuffle the pointers and notify our own caller.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Libnl3 is required for controlling Remus network buffering.
This patch adds dependency on libnl3 (>= 3.2.8) to autoconf scripts.
It also provides the ability to configure tools without libnl3 support
i.e., without network buffering support.
When there is no network buffering support, libxl__netbuffer_enabled()
returns 0, otherwise returns 1. The callers of this api will be
introduced in the rest of the series.
NOTE: This patch changes tools/configure.ac, please rerun
autogen.sh while applying the patch.
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This can be used to fork children to allow the asynchronous execution
of system calls which only come in a synchronous variant. This will
be useful for Remus, in the following patches.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
libxl__multidev_prepare_with_aodev is similar to libxl__multidev_prepare,
but takes a libxl__ao_device as an extra argument.
libxl__multidev_prepare is now a wrapper around
libxl__multidev_prepare_with_aodev.
This new internal API will be used by the Remus device abstract layer
for handling various Remus devices.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
commit: c2ba706c "tools/libxc: goto correct label on error paths" by Andrew
Cooper broke Remus in Xen 4.4 or earlier versions that has this commit
backported.
With Remus, this jump essentially discards the current incomplete checkpoint
received by the backup and restore backup from the last complete checkpoint.
This is required for Remus to work and this does not break live migration. It
has been around since Xen 4.0.
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Acked-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Make postcopy callback asynchronous.
This is a prepare patch of the following patch series.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Since xend already deleted, the old remus script which based on
xend no longer functional, remove it.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Acked-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
[ ijc -- removed "SUBDIR-y += remus" from tools/Makefile ]
Commit b327a3f421 moved the rewinding of
toolstack_save_fd to libxl. This breaks remus, because in remus mode,
toolstack_save_cb will be called in every checkpoint, and if we don't
rewind it in libxl_save_helper, it will surely fail.
This fix is just a hack: in fact the whole toolstack save thing should
be done in libxl. But for now (until migration v2) this fix should
solve both remus and Jason Adryuk's use case.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Tested-by: Jason Andryuk <andryuk@aero.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
1.introduce asynchronous execution API:
libxl__async_exec_init
libxl__async_exec_start
libxl__async_exec_inuse
2.use the async exec API to execute device hotplug scripts
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Yang Hongyang