[libvirt PATCH 1/4] conf: allow different resource registration modes
Daniel P. Berrangé
berrange at redhat.com
Fri Mar 20 13:40:11 UTC 2020
From: "Daniel P. Berrange" <berrange at redhat.com>
Currently the QEMU driver has three ways of setting up cgroups. It either
skips them entirely (if non-root), or uses systemd-machined, or uses
cgroups directly.
This change adds ability to configure the mechanism for registering
resources between all these options explicitly. via
<resource backend="none|cgroupfs|machined"/>
It is further possible to register directly with systemd and bypass
machined. We don't support this but systemd-nsspawn does and we ought
to consider this at some point. This would involve a new "systemd"
backend type alongside "machined".
Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
docs/formatdomain.html.in | 24 +++++++++++-
docs/schemas/domaincommon.rng | 17 +++++++--
src/conf/domain_conf.c | 46 ++++++++++++++++++-----
src/conf/domain_conf.h | 13 +++++++
src/libvirt_private.syms | 2 +
src/lxc/lxc_cgroup.c | 8 ++++
src/lxc/lxc_process.c | 1 +
src/qemu/qemu_cgroup.c | 14 +++++++
tests/lxcxml2xmldata/lxc-capabilities.xml | 2 +-
tests/lxcxml2xmldata/lxc-idmap.xml | 2 +-
10 files changed, 113 insertions(+), 16 deletions(-)
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 0d229386eb..a016e789f1 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -1445,7 +1445,7 @@
</p>
<pre>
...
-<resource>
+<resource backend='none|cgroupfs|machined'>
<partition>/virtualmachines/production</partition>
</resource>
...
@@ -1455,8 +1455,30 @@
Resource partitions are currently supported by the QEMU and
LXC drivers, which map partition paths to cgroups directories,
in all mounted controllers. <span class="since">Since 1.0.5</span>
+ There is a choice of implementations to use for resource partitions
+ controlled via the optional <code>backend</code> attribute.
+ <span class="since">Since 6.2.0</span>. It accepts the values
</p>
+ <ul>
+ <dt>none</dt>
+ <dd>Resource management in libvirt is disabled, with the APIs
+ returning an error indicating the functionality is not available.
+ The QEMU will will remain in whatever cgroup the libvirt daemon
+ was in. On systemd hosts, this will result in QEMU being
+ terminated at the same time as the privileged libvirt management
+ daemon which launched them.</dd>
+ <dt>cgroupfs</dt>
+ <dd>Cgroups will be directly created via the cgroups virtual filesystem.
+ This is not recommended for use in scenarios where systemd is in
+ charge of the cgroup hierarchy, unless the resource partition points
+ to a subtree that systemd has delegated administrative for.</dd>
+ <dt>machined</dt>
+ <dd>Systemd machined will be called to indirectly create cgroups.
+ This is recommended for any host where systemd is managing the
+ cgroup hierarchy.</dd>
+ </ul>
+
<h3><a id="elementsCPU">CPU model and topology</a></h3>
<p>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 6805420451..29ffc3a3cf 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -1126,9 +1126,20 @@
<define name="respartition">
<element name="resource">
- <element name="partition">
- <ref name="absFilePath"/>
- </element>
+ <optional>
+ <attribute name="backend">
+ <choice>
+ <value>none</value>
+ <value>cgroupfs</value>
+ <value>machined</value>
+ </choice>
+ </attribute>
+ </optional>
+ <optional>
+ <element name="partition">
+ <ref name="absFilePath"/>
+ </element>
+ </optional>
</element>
</define>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index e0432fc47d..ae512283d0 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -1244,6 +1244,13 @@ VIR_ENUM_IMPL(virDomainOsDefFirmware,
"efi",
);
+VIR_ENUM_IMPL(virDomainResourceBackend,
+ VIR_DOMAIN_RESOURCE_BACKEND_LAST,
+ "default",
+ "none",
+ "cgroupfs",
+ "machined");
+
/* Internal mapping: subset of block job types that can be present in
* <mirror> XML (remaining types are not two-phase). */
VIR_ENUM_DECL(virDomainBlockJob);
@@ -19100,17 +19107,24 @@ virDomainResourceDefParse(xmlNodePtr node,
{
VIR_XPATH_NODE_AUTORESTORE(ctxt);
virDomainResourceDefPtr def = NULL;
+ g_autofree char *reg = NULL;
ctxt->node = node;
if (VIR_ALLOC(def) < 0)
goto error;
- /* Find out what type of virtualization to use */
- if (!(def->partition = virXPathString("string(./partition)", ctxt))) {
- virReportError(VIR_ERR_INTERNAL_ERROR,
- "%s", _("missing resource partition attribute"));
- goto error;
+ def->partition = virXPathString("string(./partition)", ctxt);
+
+ reg = virXMLPropString(node, "backend");
+ if (reg != NULL) {
+ if ((def->backend = virDomainResourceBackendTypeFromString(reg)) <= 0) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ "%s", _("Invalid backend attribute"));
+ goto error;
+ }
+ } else {
+ def->backend = VIR_DOMAIN_RESOURCE_BACKEND_DEFAULT;
}
return def;
@@ -27983,11 +27997,23 @@ static void
virDomainResourceDefFormat(virBufferPtr buf,
virDomainResourceDefPtr def)
{
- virBufferAddLit(buf, "<resource>\n");
- virBufferAdjustIndent(buf, 2);
- virBufferEscapeString(buf, "<partition>%s</partition>\n", def->partition);
- virBufferAdjustIndent(buf, -2);
- virBufferAddLit(buf, "</resource>\n");
+ if (def->backend == VIR_DOMAIN_RESOURCE_BACKEND_DEFAULT &&
+ def->partition == NULL)
+ return;
+
+ virBufferAddLit(buf, "<resource");
+ if (def->backend != VIR_DOMAIN_RESOURCE_BACKEND_DEFAULT)
+ virBufferAsprintf(buf, " backend='%s'", virDomainResourceBackendTypeToString(def->backend));
+
+ if (def->partition) {
+ virBufferAddLit(buf, ">\n");
+ virBufferAdjustIndent(buf, 2);
+ virBufferEscapeString(buf, "<partition>%s</partition>\n", def->partition);
+ virBufferAdjustIndent(buf, -2);
+ virBufferAddLit(buf, "</resource>\n");
+ } else {
+ virBufferAddLit(buf, "/>\n");
+ }
}
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 73bd097cf8..4bfda29dee 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -2228,7 +2228,19 @@ struct _virDomainPanicDef {
void virBlkioDeviceArrayClear(virBlkioDevicePtr deviceWeights,
int ndevices);
+typedef enum {
+ VIR_DOMAIN_RESOURCE_BACKEND_DEFAULT,
+ VIR_DOMAIN_RESOURCE_BACKEND_NONE,
+ VIR_DOMAIN_RESOURCE_BACKEND_CGROUPFS,
+ VIR_DOMAIN_RESOURCE_BACKEND_MACHINED,
+
+ VIR_DOMAIN_RESOURCE_BACKEND_LAST,
+} virDomainResourceBackend;
+
+typedef struct _virDomainResourceDef virDomainResourceDef;
+typedef virDomainResourceDef *virDomainResourceDefPtr;
struct _virDomainResourceDef {
+ int backend; /* enum virDomainResourceBackend */
char *partition;
};
@@ -3525,6 +3537,7 @@ VIR_ENUM_DECL(virDomainIOMMUModel);
VIR_ENUM_DECL(virDomainVsockModel);
VIR_ENUM_DECL(virDomainShmemModel);
VIR_ENUM_DECL(virDomainLaunchSecurity);
+VIR_ENUM_DECL(virDomainResourceBackend);
/* from libvirt.h */
VIR_ENUM_DECL(virDomainState);
VIR_ENUM_DECL(virDomainNostateReason);
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 6b305bdd0e..6e5cc201ff 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -575,6 +575,8 @@ virDomainRedirdevBusTypeToString;
virDomainRedirdevDefFind;
virDomainRedirdevDefFree;
virDomainRedirdevDefRemove;
+virDomainResourceBackendTypeFromString;
+virDomainResourceBackendTypeToString;
virDomainRNGBackendTypeToString;
virDomainRNGDefFree;
virDomainRNGFind;
diff --git a/src/lxc/lxc_cgroup.c b/src/lxc/lxc_cgroup.c
index 7df723a4da..326d33981c 100644
--- a/src/lxc/lxc_cgroup.c
+++ b/src/lxc/lxc_cgroup.c
@@ -392,6 +392,14 @@ virCgroupPtr virLXCCgroupCreate(virDomainDefPtr def,
if (!machineName)
goto cleanup;
+ if (def->resource->backend != VIR_DOMAIN_RESOURCE_BACKEND_DEFAULT) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("Resource backend '%s' not available"),
+ virDomainResourceBackendTypeToString(
+ def->resource->backend));
+ goto cleanup;
+ }
+
if (def->resource->partition[0] != '/') {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("Resource partition '%s' must start with '/'"),
diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c
index 5199f3806e..4ec3cc5619 100644
--- a/src/lxc/lxc_process.c
+++ b/src/lxc/lxc_process.c
@@ -1260,6 +1260,7 @@ int virLXCProcessStart(virConnectPtr conn,
if (VIR_ALLOC(res) < 0)
goto cleanup;
+ res->backend = VIR_DOMAIN_RESOURCE_BACKEND_DEFAULT;
res->partition = g_strdup("/machine");
vm->def->resource = res;
diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index c0e30f6152..c407431f6b 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -940,11 +940,20 @@ qemuInitCgroup(virDomainObjPtr vm,
if (VIR_ALLOC(res) < 0)
goto cleanup;
+ res->backend = VIR_DOMAIN_RESOURCE_BACKEND_DEFAULT;
res->partition = g_strdup("/machine");
vm->def->resource = res;
}
+ if (vm->def->resource->backend != VIR_DOMAIN_RESOURCE_BACKEND_DEFAULT) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("Resource backend '%s' not available"),
+ virDomainResourceBackendTypeToString(
+ vm->def->resource->backend));
+ goto cleanup;
+ }
+
if (vm->def->resource->partition[0] != '/') {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("Resource partition '%s' must start with '/'"),
@@ -1061,6 +1070,11 @@ qemuConnectCgroup(virDomainObjPtr vm)
virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(priv->driver);
int ret = -1;
+ if (vm->def->resource &&
+ vm->def->resource->backend == VIR_DOMAIN_RESOURCE_BACKEND_NONE) {
+ goto done;
+ }
+
if (!virQEMUDriverIsPrivileged(priv->driver))
goto done;
diff --git a/tests/lxcxml2xmldata/lxc-capabilities.xml b/tests/lxcxml2xmldata/lxc-capabilities.xml
index 04d64e3e41..335fdf8b91 100644
--- a/tests/lxcxml2xmldata/lxc-capabilities.xml
+++ b/tests/lxcxml2xmldata/lxc-capabilities.xml
@@ -4,7 +4,7 @@
<memory unit='KiB'>1048576</memory>
<currentMemory unit='KiB'>1048576</currentMemory>
<vcpu placement='static'>1</vcpu>
- <resource>
+ <resource backend='cgroupfs'>
<partition>/machine</partition>
</resource>
<os>
diff --git a/tests/lxcxml2xmldata/lxc-idmap.xml b/tests/lxcxml2xmldata/lxc-idmap.xml
index b477636c30..d618d69706 100644
--- a/tests/lxcxml2xmldata/lxc-idmap.xml
+++ b/tests/lxcxml2xmldata/lxc-idmap.xml
@@ -4,7 +4,7 @@
<memory unit='KiB'>1048576</memory>
<currentMemory unit='KiB'>1048576</currentMemory>
<vcpu placement='static'>1</vcpu>
- <resource>
+ <resource backend='machined'>
<partition>/machine</partition>
</resource>
<os>
--
2.24.1
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