[virt-tools-list] [vhostmd virtio PATCH v3 5/6] Activate virtio support in vhostmd
Michael Trapp
Michael.Trapp at sap.com
Mon Nov 12 15:13:08 UTC 2018
Activate the virtio code and extend DTD/XML to support a virtio section
for virtio related configuration and a new transport type virtio.
---
README | 84 +++++++++++++++++++++++++++++++++++++++++----
vhostmd.changes | 5 +++
vhostmd.dtd | 6 +++-
vhostmd.xml | 6 ++++
vhostmd/Makefile.am | 4 +--
vhostmd/vhostmd.c | 61 ++++++++++++++++++++++++++++++--
6 files changed, 154 insertions(+), 12 deletions(-)
diff --git a/README b/README
index cb23226..f473079 100644
--- a/README
+++ b/README
@@ -50,8 +50,15 @@ includes a few examples of user-defined metrics, which provide a
<path>/dev/shm/vhostmd0</path>
<size unit="k">256</size>
</disk>
+ <virtio>
+ <max_channels>1024</max_channels>
+ <expiration_time>15</expiration_time>
+ <path>/var/lib/libvirt/qemu/channels</path>
+ </virtio>
<update_period>5</update_period>
<path>/usr/bin:/usr/sbin:/usr/share/vhostmd/scripts</path>
+ <transport>vbd</transport>
+ <transport>virtio</transport>
</globals>
<metrics>
<metric type="string" context="host">
@@ -115,11 +122,17 @@ includes a few examples of user-defined metrics, which provide a
</vhostmd>
A valid configuration file must contain the root element <vhostmd>.
-The <globals> element contains configuration global to vhostmd, such as
-the metrics disk path and the metrics refresh interval. The <metrics>
-element is a container for all of the <metric> elements. A metric element
-is used to define a metric, giving it a name and an action that produces
-the metric value.
+
+The <globals> element contains configuration global to vhostmd, such as the
+metrics refresh interval and the metrics transport mechanism. The <transport>
+element defines how the metrics are transported between the host and VMs. The
+vbd transport uses a virtual disk, described in the <disk> element, to share
+metrics data between host and VM. The virtio transport, described by the
+<virtio> element, uses a virtio-serial connection to share the metrics data.
+
+The <metrics> element is a container for all of the <metric> elements.
+A metric element is used to define a metric, giving it a name and an action
+that produces the metric value.
The supplied vhostmd configuration file provides a useful set of default
metrics to be collected. This can be extended or modified by editing
@@ -277,14 +290,71 @@ section:
(Note: Change target dev and bus as appropriate for the domain)
+
+Notes on Virtio Transport
+-------------------------
+
+The virtio transport uses a virtio serial device to transport metrics data
+between the host and VMs. Basically for a virtio serial device, QEMU creates
+- a unix domain socket on the Host
+- a serial port on the VM
+- 'connects' both to a 'communication channel'
+
+It can be configured in the virtio section of the vhostmd configuration file.
+<max_channels> defines the maximum number of virtio channels/VMs supported
+by the vhostmd instance with a default value of 1024.
+<expiration_time> is the time after which the virtio serial channel of a VM
+is detached when vhostmd did not receive updates. It's default value is
+'3 * update_period' of the <globals> section and the configured value is
+checked to be at least '3 * update_period'.
+<path> is the directory where the virtio serial channels are accessible and
+it must be the directory of the path attribute of QEMUs VM/channel
+configuration. The default path is '/var/lib/libvirt/qemu/channels'.
+
+ <vhostmd>
+ <globals>
+ <virtio>
+ <max_channels>1024</max_channels>
+ <expiration_time>15</expiration_time>
+ <path>/var/lib/libvirt/qemu/channels</path>
+ </virtio>
+
+Sample VM config with virtio serial:
+
+ <channel type='unix'>
+ <source mode='bind' path='/var/lib/libvirt/qemu/channels/\
+org.github.vhostmd.1.a70605c8-7d69-8c44-7e1a-5ecd092cb1e1'/>
+ <target type='virtio' name='vhostmd'/>
+ <address type='virtio-serial' controller='0' bus='0' port='1'/>
+ </channel>
+
+The name of a channel in a QEMU VM configuration must be
+ <path from vhostmd-globals-virtio-path>/org.github.vhostmd.1.<VM-UUID>
+
+
+Vhostmd accepts metric requests 'GET /metrics/XML\n\n' and responds with
+
+ <metrics>
+ <metric type='real64' context='host'>
+ <name>TotalCPUTime</name>
+ <value>179645.910000</value>
+ </metric>
+ ...
+ <metric type='uint64' context='vm' id='9' uuid='a70605c8-7d69-8c44-7e1a-5ecd092cb1e1'>
+ <name>UsedMemory</name>
+ <value>524288</value>
+ </metric>
+ </metrics>
+
+
Guest Tool/Library for Accessing Metrics Data
---------------------------------------------
Tool: vm_dump_metrics
Stand alone static utility will read all the metrics and write them
to stdout or optionally an argumented file.
- Usaga:
- vhostmd [-f dest_file]
+ Usage:
+ vm_dump_metrics -b|-i|-x [-d dest_file]
Library: libmetrics.so.0
Dynamic library that supports individual metrics gathering
diff --git a/vhostmd.changes b/vhostmd.changes
index c7b453d..c1aa06f 100644
--- a/vhostmd.changes
+++ b/vhostmd.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Wed Jul 25 10:00:20 CEST 2018 - michael.trapp at sap.com
+
+- add virtio as transport mechanism
+
-------------------------------------------------------------------
Mon Jun 29 16:42:39 MDT 2009 - jfehlig at novell.com
diff --git a/vhostmd.dtd b/vhostmd.dtd
index 471c72f..6480532 100644
--- a/vhostmd.dtd
+++ b/vhostmd.dtd
@@ -9,7 +9,7 @@ Virtual Host Metrics Daemon (vhostmd). Configuration file DTD
-->
<!ELEMENT vhostmd (globals,metrics)>
-<!ELEMENT globals (disk,update_period,path,transport+)>
+<!ELEMENT globals (disk,virtio,update_period,path,transport+)>
<!ELEMENT disk (name,path,size)>
<!ELEMENT name (#PCDATA)>
@@ -20,6 +20,10 @@ Virtual Host Metrics Daemon (vhostmd). Configuration file DTD
<!ELEMENT update_period (#PCDATA)>
<!ELEMENT transport (#PCDATA)>
+<!ELEMENT virtio (max_channels,expiration_time,path)>
+<!ELEMENT max_channels (#PCDATA)>
+<!ELEMENT expiration_time (#PCDATA)>
+
<!ELEMENT metrics (metric*)>
<!ELEMENT metric (name,action,variable*)>
<!ELEMENT action (#PCDATA)>
diff --git a/vhostmd.xml b/vhostmd.xml
index 9b048df..5400981 100644
--- a/vhostmd.xml
+++ b/vhostmd.xml
@@ -33,9 +33,15 @@ the logical && operator must be replaced with "&&".
<path>/dev/shm/vhostmd0</path>
<size unit="k">256</size>
</disk>
+ <virtio>
+ <max_channels>1024</max_channels>
+ <expiration_time>15</expiration_time>
+ <path>/var/lib/libvirt/qemu/channels</path>
+ </virtio>
<update_period>5</update_period>
<path>/usr/sbin:/sbin:/usr/bin:/bin:/usr/share/vhostmd/scripts</path>
<transport>vbd</transport>
+ <transport>virtio</transport>
<!-- <transport>xenstore</transport> -->
</globals>
<metrics>
diff --git a/vhostmd/Makefile.am b/vhostmd/Makefile.am
index 3585970..34a15e0 100644
--- a/vhostmd/Makefile.am
+++ b/vhostmd/Makefile.am
@@ -3,9 +3,9 @@ INCLUDES = \
-I../include
sbin_PROGRAMS = vhostmd
-vhostmd_SOURCES = vhostmd.c util.c metric.c virt-util.c
+vhostmd_SOURCES = vhostmd.c util.c metric.c virt-util.c virtio.c
vhostmd_CFLAGS = $(LIBXML_CFLAGS) $(LIBVIRT_CFLAGS)
-vhostmd_LDADD = -lm $(LIBXML_LIBS) $(LIBVIRT_LIBS)
+vhostmd_LDADD = -lm $(LIBXML_LIBS) $(LIBVIRT_LIBS) -lpthread
if WITH_XENSTORE
vhostmd_SOURCES += xenstore-update.c
diff --git a/vhostmd/vhostmd.c b/vhostmd/vhostmd.c
index e7ec2fc..e13fa2d 100644
--- a/vhostmd/vhostmd.c
+++ b/vhostmd/vhostmd.c
@@ -42,10 +42,11 @@
#include <time.h>
#include <libxml/parser.h>
#include <libxml/xpath.h>
+#include <pthread.h>
#include "util.h"
#include "metric.h"
-
+#include "virtio.h"
/*
* vhostmd will periodically write metrics to a disk. The metrics
@@ -85,6 +86,7 @@ typedef struct _mdisk_header
*/
#define VBD (1 << 0)
#define XENSTORE (1 << 1)
+#define VIRTIO (1 << 2)
/* Global variables */
static int down = 0;
@@ -103,6 +105,9 @@ static mdisk_header md_header =
};
static char *search_path = NULL;
static int transports = 0;
+static char *virtio_path = "/var/lib/libvirt/qemu/channels";
+static int virtio_max_channels = 1024;
+static int virtio_expiration_time = 15;
/**********************************************************************
@@ -470,6 +475,8 @@ static int parse_transports(xmlDocPtr xml,
return -1;
#endif
}
+ if (strncasecmp((char *)str, "virtio", strlen("virtio")) == 0)
+ transports |= VIRTIO;
free(str);
}
}
@@ -605,6 +612,19 @@ static int parse_config_file(const char *filename)
goto out;
}
+ if (transports & VIRTIO) {
+ char *p = NULL;
+
+ if (vu_xpath_long("string(./globals/virtio/max_channels[1])", ctxt, &l) == 0)
+ virtio_max_channels = (int)l;
+
+ if (vu_xpath_long("string(./globals/virtio/expiration_time[1])", ctxt, &l) == 0)
+ virtio_expiration_time = (int)l;
+
+ if ((p = vu_xpath_string("string(./globals/virtio/path[1])", ctxt)) != NULL)
+ virtio_path = p;
+ }
+
/* Parse requested metrics definitions */
if (parse_metrics(xml, ctxt)) {
vu_log(VHOSTMD_ERR, "Unable to parse metrics definition "
@@ -838,7 +858,8 @@ static int metrics_disk_create(void)
static int metrics_host_get(vu_buffer *buf)
{
metric *m = metrics;
-
+ unsigned start = buf->use;
+
while (m) {
if (m->ctx != METRIC_CONTEXT_HOST) {
m = m->next;
@@ -850,12 +871,18 @@ static int metrics_host_get(vu_buffer *buf)
m = m->next;
}
+
+ if (transports & VIRTIO)
+ virtio_metrics_update(&buf->content[start], (int) (buf->use - start),
+ NULL, METRIC_CONTEXT_HOST);
+
return 0;
}
static int metrics_vm_get(vu_vm *vm, vu_buffer *buf)
{
metric *m = metrics;
+ unsigned start = buf->use;
while (m) {
if (m->ctx != METRIC_CONTEXT_VM) {
@@ -868,6 +895,11 @@ static int metrics_vm_get(vu_vm *vm, vu_buffer *buf)
m = m->next;
}
+
+ if (transports & VIRTIO)
+ virtio_metrics_update(&buf->content[start], (int) (buf->use - start),
+ vm->uuid, METRIC_CONTEXT_VM);
+
return 0;
}
@@ -912,11 +944,30 @@ static int vhostmd_run(int diskfd)
int *ids = NULL;
int num_vms = 0;
vu_buffer *buf = NULL;
+ pthread_t virtio_tid;
if (vu_buffer_create(&buf, MDISK_SIZE_MIN - MDISK_HEADER_SIZE)) {
vu_log(VHOSTMD_ERR, "Unable to allocate memory");
return -1;
}
+
+ if (transports & VIRTIO) {
+ int rc;
+
+ if (virtio_expiration_time < (update_period * 3))
+ virtio_expiration_time = update_period * 3;
+
+ if (virtio_init(virtio_path, virtio_max_channels, virtio_expiration_time))
+ return -1;
+
+ rc = pthread_create(&virtio_tid, NULL, virtio_run, NULL);
+
+ if (rc != 0) {
+ vu_log(VHOSTMD_ERR, "Failed to start virtio thread '%s'\n",
+ strerror(rc));
+ return -1;
+ }
+ }
while (!down) {
time_t run_time,
@@ -948,6 +999,12 @@ static int vhostmd_run(int diskfd)
vu_buffer_erase(buf);
}
vu_buffer_delete(buf);
+
+ if (transports & VIRTIO) {
+ virtio_stop();
+ pthread_join(virtio_tid, NULL);
+ }
+
return 0;
}
--
2.17.1 (Apple Git-112)
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