The svc_probe() function makes a simple socket connection to the specified port by calling scds_fm_tcp_connect(). If the connect fails, svc_probe() returns a value of 100, which indicates a complete failure. If the connect succeeds, but the disconnect fails, svc_probe() returns a value of 50, which indicates a partial failure. If the connect and disconnect both succeed, svc_probe() returns a value of 0, which indicates success.
The code for svc_probe() is as follows:
int svc_probe(scds_handle_t scds_handle,
char *hostname, int port, int timeout)
{
int rc;
hrtime_t t1, t2;
int sock;
char testcmd[2048];
int time_used, time_remaining;
time_t connect_timeout;
/*
* probe the data service by doing a socket connection to the port
* specified in the port_list property to the host that is
* serving the XFS data service. If the XFS service which is configured
* to listen on the specified port, replies to the connection, then
* the probe is successful. Else we will wait for a time period set
* in probe_timeout property before concluding that the probe failed.
*/
/*
* Use the SVC_CONNECT_TIMEOUT_PCT percentage of timeout
* to connect to the port
*/
connect_timeout = (SVC_CONNECT_TIMEOUT_PCT * timeout)/100;
t1 = (hrtime_t)(gethrtime()/1E9);
/*
* the probe makes a connection to the specified hostname and port.
* The connection is timed for 95% of the actual probe_timeout.
*/
rc = scds_fm_tcp_connect(scds_handle, &sock, hostname, port,
connect_timeout);
if (rc) {
scds_syslog(LOG_ERR,
"Failed to connect to port <%d> of resource <%s>.",
port, scds_get_resource_name(scds_handle));
/* this is a complete failure */
return (SCDS_PROBE_COMPLETE_FAILURE);
}
t2 = (hrtime_t)(gethrtime()/1E9);
/*
* Compute the actual time it took to connect. This should be less than
* or equal to connect_timeout, the time allocated to connect.
* If the connect uses all the time that is allocated for it,
* then the remaining value from the probe_timeout that is passed to
* this function will be used as disconnect timeout. Otherwise, the
* the remaining time from the connect call will also be added to
* the disconnect timeout.
*
*/
time_used = (int)(t2 - t1);
/*
* Use the remaining time(timeout - time_took_to_connect) to disconnect
*/
time_remaining = timeout - (int)time_used;
/*
* If all the time is used up, use a small hardcoded timeout
* to still try to disconnect. This will avoid the fd leak.
*/
if (time_remaining <= 0) {
scds_syslog_debug(DBG_LEVEL_LOW,
"svc_probe used entire timeout of "
"%d seconds during connect operation and exceeded the "
"timeout by %d seconds. Attempting disconnect with timeout"
" %d ",
connect_timeout,
abs(time_used),
SVC_DISCONNECT_TIMEOUT_SECONDS);
time_remaining = SVC_DISCONNECT_TIMEOUT_SECONDS;
}
/*
* Return partial failure in case of disconnection failure.
* Reason: The connect call is successful, which means
* the application is alive. A disconnection failure
* could happen due to a hung application or heavy load.
* If it is the later case, don't declare the application
* as dead by returning complete failure. Instead, declare
* it as partial failure. If this situation persists, the
* disconnect call will fail again and the application will be
* restarted.
*/
rc = scds_fm_tcp_disconnect(scds_handle, sock, time_remaining);
if (rc != SCHA_ERR_NOERR) {
scds_syslog(LOG_ERR,
"Failed to disconnect to port %d of resource %s.",
port, scds_get_resource_name(scds_handle));
/* this is a partial failure */
return (SCDS_PROBE_COMPLETE_FAILURE/2);
}
t2 = (hrtime_t)(gethrtime()/1E9);
time_used = (int)(t2 - t1);
time_remaining = timeout - time_used;
/*
* If there is no time left, don't do the full test with
* fsinfo. Return SCDS_PROBE_COMPLETE_FAILURE/2
* instead. This will make sure that if this timeout
* persists, server will be restarted.
*/
if (time_remaining <= 0) {
scds_syslog(LOG_ERR, "Probe timed out.");
return (SCDS_PROBE_COMPLETE_FAILURE/2);
}
/*
* The connection and disconnection to port is successful,
* Run the fsinfo command to perform a full check of
* server health.
* Redirect stdout, otherwise the output from fsinfo
* ends up on the console.
*/
(void) sprintf(testcmd,
"/usr/openwin/bin/fsinfo -server %s:%d > /dev/null",
hostname, port);
scds_syslog_debug(DBG_LEVEL_HIGH,
"Checking the server status with %s.", testcmd);
if (scds_timerun(scds_handle, testcmd, time_remaining,
SIGKILL, &rc) != SCHA_ERR_NOERR || rc != 0) {
scds_syslog(LOG_ERR,
"Failed to check server status with command <%s>",
testcmd);
return (SCDS_PROBE_COMPLETE_FAILURE/2);
}
return (0);
}When finished, svc_probe() returns a value that indicates success (0), partial failure (50), or complete failure (100). The xfnts_probe method passes this value to scds_fm_action().