SAM_INITIALIZE(3) Corosync Cluster Engine Programmer's Manual SAM_INITIALIZE(3)

sam_initialize - Initialize health checking

#include <corosync/sam.h>

cs_error_t sam_initialize (int time_interval, sam_recovery_policy_t recovery_policy);

The sam_initialize function is used to initialize health checking of a process.

Application can have only one instance of SAM. This function must be called before any other of SAM functions. It is recommended to initialize before the process begins any process initialization.

The time_interval parameter is a timeout in milliseconds before taking recovery action after having not received a healthcheck.

If time_interval parameter is zero, there is no time limit and no healthcheck must be sent by the process. In this operational mode, a process failure will continue to execute the recovery policy.

The recovery_policy is defined as type:

  typedef enum {
  	SAM_RECOVERY_POLICY_QUIT = 1,
  	SAM_RECOVERY_POLICY_RESTART = 2,
        SAM_RECOVERY_POLICY_QUORUM = 0x08,
        SAM_RECOVERY_POLICY_QUORUM_QUIT = SAM_RECOVERY_POLICY_QUORUM | SAM_RECOVERY_POLICY_QUIT,
        SAM_RECOVERY_POLICY_QUORUM_RESTART = SAM_RECOVERY_POLICY_QUORUM | SAM_RECOVERY_POLICY_RESTART,
        SAM_RECOVERY_POLICY_CMAP = 0x10,
        SAM_RECOVERY_POLICY_CONFDB = 0x10,
  } sam_recovery_policy_t;

where

on failure, the process will terminate.
on failure, the process will restart.
is not policy. Used only as flag meaning quorum integration
same as SAM_RECOVERY_POLICY_QUIT but sam_start (3) will block until corosync becomes quorate and process will be terminated if quorum is lost.
same as SAM_RECOVERY_POLICY_RESTART but sam_start (3) will block until corosync becomes quorate and process will be restarted if quorum is lost.
is not policy. Used only as flag meaning cmap integration. It can be used with all previous policies. For backward compatibility, SAM_RECOVERY_POLICY_CONFDB with same meaning as SAM_RECOVERY_POLICY_CMAP is also provided.

To perform event driven healthchecking, sam_register(3) and sam_start(3) functions must called. Event driven healthchecking causes the duplicate standby process running the SAM serve rto periodically request healthchecks from the active process.

This call return CS_OK value if successful, otherwise and error is returned.

can happened in case of double initialization.
recovery_policy has invalid value.

sam_register(3), sam_start(3), sam_hc_callback_register(3)

CS_ERR_TRY_AGAIN Resource temporarily unavailable

CS_ERR_INVALID_PARAM Invalid argument

CS_ERR_ACCESS Permission denied

CS_ERR_LIBRARY The connection failed

CS_ERR_INTERRUPT System call interrupted by a signal

CS_ERR_NOT_SUPPORTED The requested protocol/functionality not supported

CS_ERR_MESSAGE_ERROR Incorrect auth message received

CS_ERR_NO_MEMORY Not enough memory to complete the requested task

21/05/2010 corosync Man Page