public synchronized boolean createStorageID(StorageDirectory sd, boolean regenerateStorageIds) {
final String oldStorageID = sd.getStorageUuid();
if (oldStorageID == null || regenerateStorageIds) {
sd.setStorageUuid(DatanodeStorage.generateUuid());
LOG.info(
"Generated new storageID "
+ sd.getStorageUuid()
+ " for directory "
+ sd.getRoot()
+ (oldStorageID == null ? "" : (" to replace " + oldStorageID)));
return true;
}
return false;
}
void format(StorageDirectory sd, NamespaceInfo nsInfo, String datanodeUuid) throws IOException {
sd.clearDirectory();
this.layoutVersion = HdfsConstants.DATANODE_LAYOUT_VERSION;
this.clusterID = nsInfo.getClusterID();
this.namespaceID = nsInfo.getNamespaceID();
this.cTime = 0;
setDatanodeUuid(datanodeUuid);
if (sd.getStorageUuid() == null) {
// 分配新的 Storage UUID.
sd.setStorageUuid(DatanodeStorage.generateUuid());
}
writeProperties(sd);
}
private void setFieldsFromProperties(
Properties props, StorageDirectory sd, boolean overrideLayoutVersion, int toLayoutVersion)
throws IOException {
if (overrideLayoutVersion) {
this.layoutVersion = toLayoutVersion;
} else {
setLayoutVersion(props, sd);
}
setcTime(props, sd);
checkStorageType(props, sd);
setClusterId(props, layoutVersion, sd);
if (!DataNodeLayoutVersion.supports(LayoutVersion.Feature.FEDERATION, layoutVersion)) {
setNamespaceID(props, sd);
}
String ssid = props.getProperty("storageID");
if (ssid == null) {
throw new InconsistentFSStateException(
sd.getRoot(), "file " + STORAGE_FILE_VERSION + " is invalid.");
}
String sid = sd.getStorageUuid();
if (!(sid == null || sid.equals("") || ssid.equals("") || sid.equals(ssid))) {
throw new InconsistentFSStateException(sd.getRoot(), "具有不兼容的存储标识。");
}
if (sid == null) { // update id only if it was null
sd.setStorageUuid(ssid);
}
if (props.getProperty("datanodeUuid") != null) {
String dnUuid = props.getProperty("datanodeUuid");
if (getDatanodeUuid() == null) {
setDatanodeUuid(dnUuid);
} else if (getDatanodeUuid().compareTo(dnUuid) != 0) {
throw new InconsistentFSStateException(
sd.getRoot(),
"Root "
+ sd.getRoot()
+ ": DatanodeUuid="
+ dnUuid
+ ", does not match "
+ getDatanodeUuid()
+ " from other"
+ " StorageDirectory.");
}
}
}
@Override
protected void setPropertiesFromFields(Properties props, StorageDirectory sd) throws IOException {
props.setProperty("storageType", storageType.toString());
props.setProperty("clusterID", clusterID);
props.setProperty("cTime", String.valueOf(cTime));
props.setProperty("layoutVersion", String.valueOf(layoutVersion));
props.setProperty("storageID", sd.getStorageUuid());
String datanodeUuid = getDatanodeUuid();
if (datanodeUuid != null) {
props.setProperty("datanodeUuid", datanodeUuid);
}
// Set NamespaceID in version before federation
if (!DataNodeLayoutVersion.supports(LayoutVersion.Feature.FEDERATION, layoutVersion)) {
props.setProperty("namespaceID", String.valueOf(namespaceID));
}
}
private void doTransition(
DataNode datanode, StorageDirectory sd, NamespaceInfo nsInfo, StartupOption startOpt)
throws IOException {
if (startOpt == StartupOption.ROLLBACK) {
throw new RuntimeException("未实现");
}
readProperties(sd);
checkVersionUpgradable(this.layoutVersion);
// 版本号为负数，越小越高,文件里面的layoutVersion必须比hadoop版本大或者等于
assert this.layoutVersion >= HdfsConstants.DATANODE_LAYOUT_VERSION : "不允许将来的版本";
boolean federationSupported =
DataNodeLayoutVersion.supports(LayoutVersion.Feature.FEDERATION, layoutVersion);
if (!federationSupported && getNamespaceID() != nsInfo.getNamespaceID()) {
throw new IOException(
"Incompatible namespaceIDs in "
+ sd.getRoot().getCanonicalPath()
+ ": namenode namespaceID = "
+ nsInfo.getNamespaceID()
+ "; datanode namespaceID = "
+ getNamespaceID());
}
if (federationSupported && !getClusterID().equals(nsInfo.getClusterID())) {
throw new IOException(
"Incompatible clusterIDs in "
+ sd.getRoot().getCanonicalPath()
+ ": namenode clusterID = "
+ nsInfo.getClusterID()
+ "; datanode clusterID = "
+ getClusterID());
}
boolean haveValidStorageId =
DataNodeLayoutVersion.supports(
LayoutVersion.Feature.ADD_DATANODE_AND_STORAGE_UUIDS, layoutVersion)
&& DatanodeStorage.isValidStorageId(sd.getStorageUuid());
if (this.layoutVersion == HdfsConstants.DATANODE_LAYOUT_VERSION) {
createStorageID(sd, !haveValidStorageId);
return;
}
throw new IOException(
"BUG: The stored LV = "
+ this.getLayoutVersion()
+ " is newer than the supported LV = "
+ HdfsConstants.DATANODE_LAYOUT_VERSION);
}
