[KVM] Enable IOURING only when it is available on the host

agent/conf/agent.properties

@@ -286,5 +286,5 @@ iscsi.session.cleanup.enabled=false
 # Enable manually setting CPU's topology on KVM's VM.
 # enable.manually.setting.cpu.topology.on.kvm.vm=true
 
-# Enable/disable IO driver for Qemu / It's enabled by default on KVM agents
+# Enable/disable IO driver for Qemu (in case it is not set CloudStack can also detect if its supported by qemu)
 # enable.io.uring=true

agent/src/main/java/com/cloud/agent/properties/AgentProperties.java

@@ -54,13 +54,6 @@ public class AgentProperties{
  */
  public static final Property<Boolean> ENABLE_MANUALLY_SETTING_CPU_TOPOLOGY_ON_KVM_VM = new Property<Boolean>("enable.manually.setting.cpu.topology.on.kvm.vm", true);
 
- /**
- * Enable manually IO driver on KVM's VM. <br>
- * Data type: boolean.<br>
- * Default value: true.
- */
- public static final Property<Boolean> ENABLE_IO_URING = new Property<Boolean>("enable.io.uring", true);
-
  public static class Property <T>{
  private final String name;
  private final T defaultValue;

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtComputingResource.java

@@ -313,6 +313,8 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
 
  public final static String HOST_CACHE_PATH_PARAMETER = "host.cache.location";
  public final static String CONFIG_DIR = "config";
+ private boolean enableIoUring;
+ private final static String ENABLE_IO_URING_PROPERTY = "enable.io.uring";
 
  public static final String BASH_SCRIPT_PATH = "/bin/bash";
 
@@ -1132,6 +1134,12 @@ public boolean configure(final String name, final Map<String, Object> params) th
  s_logger.trace("Ignoring libvirt error.", e);
  }
 
+ // Enable/disable IO driver for Qemu (in case it is not set CloudStack can also detect if its supported by qemu)
+ // Do not remove - switching it to AgentProperties.Property may require accepting null values for the properties default value
+ String enableIoUringConfig = (String) params.get(ENABLE_IO_URING_PROPERTY);
+ enableIoUring = isIoUringEnabled(enableIoUringConfig);
+ s_logger.info("IO uring driver for Qemu: " + (enableIoUring ? "enabled" : "disabled"));
+
  final String cpuArchOverride = (String)params.get("guest.cpu.arch");
  if (!Strings.isNullOrEmpty(cpuArchOverride)) {
  _guestCpuArch = cpuArchOverride;
@@ -2949,20 +2957,68 @@ private KVMPhysicalDisk getPhysicalDiskPrimaryStore(PrimaryDataStoreTO primaryDa
  return storagePool.getPhysicalDisk(data.getPath());
  }
 
+ /**
+ * Check if IO_URING is supported by qemu
+ */
+ protected boolean isIoUringSupportedByQemu() {
+ s_logger.debug("Checking if iouring is supported");
+ String command = getIoUringCheckCommand();
+ if (org.apache.commons.lang3.StringUtils.isBlank(command)) {
+ s_logger.debug("Could not check iouring support, disabling it");
+ return false;
+ }
+ int exitValue = executeBashScriptAndRetrieveExitValue(command);
+ return exitValue == 0;
+ }
+
+ protected String getIoUringCheckCommand() {
+ String[] qemuPaths = { "/usr/bin/qemu-system-x86_64", "/usr/libexec/qemu-kvm", "/usr/bin/qemu-kvm" };
+ for (String qemuPath : qemuPaths) {
+ File file = new File(qemuPath);
+ if (file.exists()) {
+ String cmd = String.format("ldd %s | grep -Eqe '[[:space:]]liburing\\.so'", qemuPath);
+ s_logger.debug("Using the check command: " + cmd);
+ return cmd;
+ }
+ }
+ return null;
+ }
+
  /**
  * Set Disk IO Driver, if supported by the Libvirt/Qemu version.
  * IO Driver works for:
  * (i) Qemu >= 5.0;
  * (ii) Libvirt >= 6.3.0
  */
  protected void setDiskIoDriver(DiskDef disk) {
- if (getHypervisorLibvirtVersion() >= HYPERVISOR_LIBVIRT_VERSION_SUPPORTS_IO_URING
- && getHypervisorQemuVersion() >= HYPERVISOR_QEMU_VERSION_SUPPORTS_IO_URING
- && AgentPropertiesFileHandler.getPropertyValue(AgentProperties.ENABLE_IO_URING)) {
+ if (enableIoUring) {
  disk.setIoDriver(DiskDef.IoDriver.IOURING);
  }
  }
 
+ /**
+ * IO_URING supported if the property 'enable.io.uring' is set to true OR it is supported by qemu
+ */
+ private boolean isIoUringEnabled(String enableIoUringConfig) {
+ boolean meetRequirements = getHypervisorLibvirtVersion() >= HYPERVISOR_LIBVIRT_VERSION_SUPPORTS_IO_URING
+ && getHypervisorQemuVersion() >= HYPERVISOR_QEMU_VERSION_SUPPORTS_IO_URING;
+ if (!meetRequirements) {
+ return false;
+ }
+ return enableIoUringConfig != null ?
+ Boolean.parseBoolean(enableIoUringConfig):
+ (isBaseOsUbuntu() || isIoUringSupportedByQemu());
+ }
+
+ private boolean isBaseOsUbuntu() {
+ Map<String, String> versionString = getVersionStrings();
+ String hostKey = "Host.OS";
+ if (MapUtils.isEmpty(versionString) || !versionString.containsKey(hostKey) || versionString.get(hostKey) == null) {
+ return false;
+ }
+ return versionString.get(hostKey).equalsIgnoreCase("ubuntu");
+ }
+
  private KVMPhysicalDisk getPhysicalDiskFromNfsStore(String dataStoreUrl, DataTO data) {
  final String volPath = dataStoreUrl + File.separator + data.getPath();
  final int index = volPath.lastIndexOf("/");
@@ -3826,10 +3882,20 @@ public List<DiskDef> getDisks(final Connect conn, final String vmName) {
  }
 
  private String executeBashScript(final String script) {
+ return createScript(script).execute();
+ }
+
+ private Script createScript(final String script) {
  final Script command = new Script("/bin/bash", _timeout, s_logger);
  command.add("-c");
  command.add(script);
- return command.execute();
+ return command;
+ }
+
+ private int executeBashScriptAndRetrieveExitValue(final String script) {
+ Script command = createScript(script);
+ command.execute();
+ return command.getExitValue();
  }
 
  public List<VmNetworkStatsEntry> getVmNetworkStat(Connect conn, String vmName) throws LibvirtException {