in zookeeper-server/src/main/java/org/apache/zookeeper/Login.java [101:276]
public Login(final String loginContextName, Supplier<CallbackHandler> callbackHandlerSupplier, final ZKConfig zkConfig) throws LoginException {
this.zkConfig = zkConfig;
this.callbackHandlerSupplier = callbackHandlerSupplier;
login = login(loginContextName);
this.loginContextName = loginContextName;
subject = login.getSubject();
isKrbTicket = !subject.getPrivateCredentials(KerberosTicket.class).isEmpty();
AppConfigurationEntry[] entries = Configuration.getConfiguration().getAppConfigurationEntry(loginContextName);
for (AppConfigurationEntry entry : entries) {
// there will only be a single entry, so this for() loop will only be iterated through once.
if (entry.getOptions().get("useTicketCache") != null) {
String val = (String) entry.getOptions().get("useTicketCache");
if (val.equals("true")) {
isUsingTicketCache = true;
}
}
if (entry.getOptions().get("principal") != null) {
principal = (String) entry.getOptions().get("principal");
}
break;
}
if (!isKrbTicket) {
// if no TGT, do not bother with ticket management.
return;
}
// Refresh the Ticket Granting Ticket (TGT) periodically. How often to refresh is determined by the
// TGT's existing expiry date and the configured MIN_TIME_BEFORE_RELOGIN. For testing and development,
// you can decrease the interval of expiration of tickets (for example, to 3 minutes) by running :
// "modprinc -maxlife 3mins <principal>" in kadmin.
t = new Thread(new Runnable() {
public void run() {
LOG.info("TGT refresh thread started.");
while (true) { // renewal thread's main loop. if it exits from here, thread will exit.
KerberosTicket tgt = getTGT();
long now = Time.currentWallTime();
long nextRefresh;
Date nextRefreshDate;
if (tgt == null) {
nextRefresh = now + MIN_TIME_BEFORE_RELOGIN;
nextRefreshDate = new Date(nextRefresh);
LOG.warn("No TGT found: will try again at {}", nextRefreshDate);
} else {
nextRefresh = getRefreshTime(tgt);
long expiry = tgt.getEndTime().getTime();
Date expiryDate = new Date(expiry);
if ((isUsingTicketCache) && (tgt.getEndTime().equals(tgt.getRenewTill()))) {
LOG.error(
"The TGT cannot be renewed beyond the next expiry date: {}."
+ "This process will not be able to authenticate new SASL connections after that "
+ "time (for example, it will not be authenticate a new connection with a Zookeeper "
+ "Quorum member). Ask your system administrator to either increase the "
+ "'renew until' time by doing : 'modprinc -maxrenewlife {}' within "
+ "kadmin, or instead, to generate a keytab for {}. Because the TGT's "
+ "expiry cannot be further extended by refreshing, exiting refresh thread now.",
expiryDate,
principal,
principal);
return;
}
// determine how long to sleep from looking at ticket's expiry.
// We should not allow the ticket to expire, but we should take into consideration
// MIN_TIME_BEFORE_RELOGIN. Will not sleep less than MIN_TIME_BEFORE_RELOGIN, unless doing so
// would cause ticket expiration.
if ((nextRefresh > expiry) || ((now + MIN_TIME_BEFORE_RELOGIN) > expiry)) {
// expiry is before next scheduled refresh).
nextRefresh = now;
} else {
if (nextRefresh < (now + MIN_TIME_BEFORE_RELOGIN)) {
// next scheduled refresh is sooner than (now + MIN_TIME_BEFORE_LOGIN).
Date until = new Date(nextRefresh);
Date newuntil = new Date(now + MIN_TIME_BEFORE_RELOGIN);
LOG.warn(
"TGT refresh thread time adjusted from : {} to : {} since "
+ "the former is sooner than the minimum refresh interval ("
+ "{} seconds) from now.",
until,
newuntil,
(MIN_TIME_BEFORE_RELOGIN / 1000));
}
nextRefresh = Math.max(nextRefresh, now + MIN_TIME_BEFORE_RELOGIN);
}
nextRefreshDate = new Date(nextRefresh);
if (nextRefresh > expiry) {
LOG.error(
"next refresh: {} is later than expiry {}."
+ " This may indicate a clock skew problem."
+ " Check that this host and the KDC's "
+ "hosts' clocks are in sync. Exiting refresh thread.",
nextRefreshDate,
expiryDate);
return;
}
}
if (now == nextRefresh) {
LOG.info("refreshing now because expiry is before next scheduled refresh time.");
} else if (now < nextRefresh) {
Date until = new Date(nextRefresh);
LOG.info("TGT refresh sleeping until: {}", until.toString());
try {
Thread.sleep(nextRefresh - now);
} catch (InterruptedException ie) {
LOG.warn("TGT renewal thread has been interrupted and will exit.");
break;
}
} else {
LOG.error(
"nextRefresh:{} is in the past: exiting refresh thread. Check"
+ " clock sync between this host and KDC - (KDC's clock is likely ahead of this host)."
+ " Manual intervention will be required for this client to successfully authenticate."
+ " Exiting refresh thread.",
nextRefreshDate);
break;
}
if (isUsingTicketCache) {
String cmd = zkConfig.getProperty(ZKConfig.KINIT_COMMAND, KINIT_COMMAND_DEFAULT);
String kinitArgs = "-R";
int retry = 1;
while (retry >= 0) {
try {
LOG.debug("running ticket cache refresh command: {} {}", cmd, kinitArgs);
Shell.execCommand(cmd, kinitArgs);
break;
} catch (Exception e) {
if (retry > 0) {
--retry;
// sleep for 10 seconds
try {
sleepBeforeRetryFailedRefresh();
} catch (InterruptedException ie) {
LOG.error("Interrupted while renewing TGT, exiting Login thread");
return;
}
} else {
LOG.warn(
"Could not renew TGT due to problem running shell command: '{} {}'."
+ " Exiting refresh thread.",
cmd,
kinitArgs,
e);
return;
}
}
}
}
try {
int retry = 1;
while (retry >= 0) {
try {
reLogin();
break;
} catch (LoginException le) {
if (retry > 0) {
--retry;
// sleep for 10 seconds.
try {
sleepBeforeRetryFailedRefresh();
} catch (InterruptedException e) {
LOG.error("Interrupted during login retry after LoginException:", le);
throw le;
}
} else {
LOG.error("Could not refresh TGT for principal: {}.", principal, le);
}
}
}
} catch (LoginException le) {
LOG.error("Failed to refresh TGT: refresh thread exiting now.", le);
break;
}
}
}
});
t.setDaemon(true);
}