• virDomainShutdown(virDomainPtr domain)
• virDomainShutdownFlags(virDomainPtr domain, unsigned int flags)

• virDomainCoreDump(virDomainPtr dom, const char *to, unsigned int flags)
• virDomainCoreDumpWithFormat(
virDomainPtr dom, const char *to, unsigned int fmt, unsigned int flags)

• virDomainCreate(virDomainPtr dom)
• virDomainCreateWithFlags(
virDomainPtr dom, unsigned int flags)
• virDomainCreateWithFiles(
virDomainPtr dom, unsigned int nfiles, int *files, unsigned int flags)

int numActive, *idList, i;

numActive = virConnectNumOfDomains(conn);
idList = malloc(sizeof(int) * numActive);
virConnectListDomains(conn, idList, numActive);

for (i = 0; i < numActive; i++) {
  virDomainPtr dom = virDomainLookupByID(conn, idList[i]);
  /* Do something useful with @dom. */
}

From bare C and glibc:

free(NULL);

Not in libvirt:

virDomainFree(NULL); /* Causes an error */
virDomainInterfaceFree(NULL); /* No error */

• virDomainDestroy()

• <controller type='pci' model='pcie-root-port'>
  <model name='ioh3420'/>
</controller>

• <xml/>

• Introducing a new feature sometimes means rewriting a significant portion of directly not related code

• Majority of our API is internal
• For instance, many requests for turning virCommand into a separate library

• Objects are not exposed to user
• Public header file:
  typedef struct _virDomain virDomain;
• Private file: struct _virDomain { ... };

virConnect object has been adjusted more than 20 times.

• Historical reasons
  • Libvirt started as a Xen wrapper
• Changing requirements
  • Hard to do proper analysis and design

• Many one-man-show drivers
  • Lacking knowledge of approaches though all HVs
• Downstream deadlines
  • APIs pushed without driver implementation

• Hard to follow traditional SE models (e.g.waterfall model)
• OSS is able to go back and forth in SE models

• Perhaps some agile methodologies
• Daily SCRUM over IRC?

eXtreme Programming has some answers:

• Refactor
• Write tests (both unit and integration)
• Release often

• We did some mistakes, but we've learned from them
• Use common sense
• Be nice to new contributors