[Libvir] [RFC] Life-cycle Management of the domain

[Saori Fukuta]

On Fri, 20 Apr 2007 14:31:02 +0100 "Daniel P. Berrange" wrote:
> > > If we ignore case B, I think we still have lots of interesting
> > > combos to think about:
> > > 
> > >   1. Static - change persistent config
> > >   2. Dynamic - change live VM config
> > >   3. Static and Dynamic - change persistent config, and live VM
> > >   4. Static or Dynamic - if domain is inactive, change persistent
> > >                          config, if it is active, change live VM
> > > 
>
> This is already possible today actually. In Xen 3.0.4 or later there is the
> lifecycle management APIs, so there is an API which lets you define a config
> for a guest. So in this case we just convert from XML -> SEXPR, in the same
> way that we do to boot a guest.  For older Xen, we simply write files straight
> into /etc/xen.  The QEMUD daemon stores the XML files for QEMU/KVM in the
> native libvirt format, so that's easy.

So it will be possible following way using new API right ?

new API: virDomainSetMemoryScope(virDomainPtr dom, int mem, int scope);

>    virsh setmem foo 500                    -> VIR_DOMAIN_SCOPE_CURRENT(4)
>    virsh --static setmem foo 500           -> VIR_DOMAIN_SCOPE_STATIC(1)
>    virsh --dynamic setmem foo 500          -> VIR_DOMAIN_SCOPE_DYNAMIC(2)
>    virsh --static --dynamic setmem foo 500 -> VIR_DOMAIN_SCOPE_BOTH(3)

    When scope is VIR_DOMAIN_SCOPE_CURRENT, execute current handling.

    When scope is other, execute as follows:
        1. get the config using domainDumpXML
        2. change the value of memory
           -> When scope is VIR_DOMAIN_SCOPE_STATIC or VIR_DOMAIN_SCOPE_BOTH:
              - change the value of currentMemory on the config
           -> When scope is VIR_DOMAIN_SCOPE_DYNAMIC or VIR_DOMAIN_SCOPE_BOTH:
              - change the actual memory allocation using domainSetMemory
        3. define the config using domainDefineXML

Here is example. (NOTE: not compiled or tested. need error handling)
Index: virsh.c
===================================================================
RCS file: /data/cvs/libvirt/src/virsh.c,v
retrieving revision 1.73
diff -u -p -r1.73 virsh.c
--- virsh.c     13 Apr 2007 08:04:08 -0000      1.73
+++ virsh.c     23 Apr 2007 08:55:55 -0000
@@ -1461,6 +1461,9 @@ cmdSetmem(vshControl * ctl, vshCmd * cmd
     virDomainPtr dom;
     int kilobytes;
     int ret = TRUE;
+    int op_static = vshCommandOptBool(cmd, "static");
+    int op_dynamic = vshCommandOptBool(cmd, "dynamic");
+    int flag = VIR_DOMAIN_SCOPE_CURRENT;

     if (!vshConnectionUsability(ctl, ctl->conn, TRUE))
         return FALSE;
@@ -1475,7 +1478,14 @@ cmdSetmem(vshControl * ctl, vshCmd * cmd
         return FALSE;
     }

-    if (virDomainSetMemory(dom, kilobytes) != 0) {
+    if (op_static && op_dynamic) {
+        flag = VIR_DOMAIN_SCOPE_BOTH;
+    } else if (op_static) {
+        flag = VIR_DOMAIN_SCOPE_STATIC;
+    } else if (op_static) {
+        flag = VIR_DOMAIN_SCOPE_DYNAMIC;
+    }
+    if (virDomainSetMemoryScope(dom, kilobytes, flag) !=0) {
         ret = FALSE;
     }

Index: libvirt.c
===================================================================
RCS file: /data/cvs/libvirt/src/libvirt.c,v
retrieving revision 1.68
diff -u -p -r1.68 libvirt.c
--- libvirt.c   18 Apr 2007 10:14:07 -0000      1.68
+++ libvirt.c   23 Apr 2007 08:56:14 -0000
@@ -1304,6 +1304,55 @@ virDomainSetMemory(virDomainPtr domain,
     return -1;
 }

+int
+virDomainSetMemoryScope(virDomainPtr domain, unsigned long memory, int scope)
+{
+    virConnectPtr conn;
+    char *dump;
+    virDomainPtr dom;
+
+    if (domain == NULL) {
+        TODO
+        return (-1);
+    }
+    if (!VIR_IS_CONNECTED_DOMAIN(domain)) {
+        virLibDomainError(domain, VIR_ERR_INVALID_DOMAIN, __FUNCTION__);
+        return (-1);
+    }
+    if (domain->conn->flags & VIR_CONNECT_RO) {
+        virLibDomainError(domain, VIR_ERR_OPERATION_DENIED, __FUNCTION__);
+        return (-1);
+    }
+    if (memory < 4096) {
+        virLibDomainError(domain, VIR_ERR_INVALID_ARG, __FUNCTION__);
+        return (-1);
+    }
+
+    conn = domain->conn;
+
+    if (scope == VIR_DOMAIN_SCOPE_CURRENT){
+        if (conn->driver->domainSetMemory)
+            return conn->driver->domainSetMemory (domain, memory);
+    } else {
+        if (conn->driver->domainDumpXML)
+            dump = conn->driver->domainDumpXML (domain, 0);
+        switch (scope) {
+            case VIR_DOMAIN_SCOPE_STATIC:
+                /* change the value of currentMemory */
+            case VIR_DOMAIN_SCOPE_DYNAMIC:
+                /* change the actual memory allocation using domainSetMemory */
+            case VIR_DOMAIN_SCOPE_BOTH:
+                /* change the value of currentMemory */
+        }
+        if (conn->driver->domainDefineXML)
+            dom = conn->driver->domainDefineXML (conn, dump);
+    }
+
+    virLibConnError (conn, VIR_ERR_CALL_FAILED, __FUNCTION__);
+    return -1;
+}


Thanks,
Saori Fukuta.