NAME

clu_info, clu_get_info, clu_free_info, clu_get_memb_by_name, clu_get_memb_by_id, clu_free_memb − Gets information about a cluster and its members

SYNOPSIS

#include <sys/clu.h>
int clu_info(
        int clu_info_type,
        ... ); int clu_info(
        CLU_INFO_MEMBSTATE,
        size_t memb_array_size,
        char ∗member_array ); int clu_info(
        CLU_INFO_LIMITS,
        struct clu_limits ∗limits ); int clu_info(
        CLU_INFO_CLU_NAME,
        char ∗name,
        size_t size ); int clu_info(
        CLU_INFO_INTERNAME_BY_ID,
        memberid_t memberid,
        char ∗intername,
        size_t size ); int clu_info(
        CLU_INFO_INTERNAME_BY_NAME,
        char ∗hostname,
        char ∗intername,
        size_t size ); int clu_info(
        CLU_INFO_HOSTNAME_BY_ID,
        memberid_t memberid,
        char ∗hostname_out,
        size_t size ); int clu_info(
        CLU_INFO_NODENAME_BY_ID,
        memberid_t memberid,
        char ∗nodename,
        size_t size ); int clu_info(
        CLU_INFO_NODENAME_BY_NAME,
        char ∗hostname,
        char ∗nodename,
        size_t size ); int clu_info(
        CLU_INFO_MEMBERID_BY_NAME,
        char ∗hostname,
        memberid_t ∗memberid_out ); int clu_info(
        CLU_INFO_MEMBLIST,
        char ∗∗namelist,
        size_t ∗array_size,
        size_t name_length ); int clu_info(
        CLU_INFO_MY_ID,
        memberid_t ∗my_memberid ); int clu_get_info(
        struct clu_gen_info ∗∗clu_gen_ptr ); void clu_free_info(
        struct clu_gen_info ∗∗clu_gen_ptr ); int clu_get_memb_by_name(
        char ∗hostname,
        struct clu_member_info ∗∗clu_memb_ptr ); int clu_get_memb_by_id(
        memberid_t memberid,
        struct clu_member_info ∗∗clu_memb_ptr ); int clu_free_memb(
        struct clu_member_info ∗∗clu_memb_ptr );

LIBRARY

Cluster Library (libclu)

PARAMETERS

clu_info_type
One of the information constants defined in <sys/clu.h>: CLU_INFO_MEMBSTATE, CLU_INFO_LIMITS, CLU_INFO_CLU_NAME, CLU_INFO_INTERNAME_BY_ID, CLU_INFO_INTERNAME_BY_NAME, CLU_INFO_HOSTNAME_BY_ID, CLU_INFO_NODENAME_BY_ID, CLU_INFO_NODENAME_BY_NAME, CLU_INFO_MEMBERID_BY_NAME, CLU_INFO_MEMBLIST, CLU_INFO_MY_ID. These constants specify the type of cluster query being made. 

array_size
Number of elements in the namelist array. 

hostname
String containing the host name used to specify the cluster member for which to retrieve information.

hostname_out
Pointer to a caller-allocated buffer that holds a string, which clu_info() fills with the host name of the specified member. 

intername
Pointer to a caller-allocated buffer that holds a string, which clu_info() fills with the interconnect host name. 

limits
A caller-allocated structure of type struct clu_limits, which clu_info() will fill with the minimum supported member ID, the maximum supported member ID, and the maximum supported number of members in a cluster. 

memb_array_size
Number of elements in the member_array array. 

member_array
Pointer to a caller-allocated character array that will hold information about each member’s state. The size of the array should be CLU_MAX_MEMBERID + 1.  The element of the array that matches the member ID of a member will contain that member’s current state: CLU_MEMB_NOT_CONF (-1), CLU_MEMB_CONF_DOWN (0), or CLU_MEMB_CONF_UP (1).  For example, member_array[2] will contain the state of member 2. 

memberid
Member ID of the cluster member for which to retrieve information.

memberid_out
Pointer to a variable of type memberid_t which will be set to the member ID of the specified member. 

my_memberid
Pointer to a variable of type memberid_t which will be set to the member ID of the running cluster member. 

name
Pointer to a caller-allocated buffer that holds a string, which clu_info() will fill with the cluster name. 

namelist
Pointer to a caller-allocated array that will hold the host names of all members in the cluster.

name_length
The caller-allocated size of each string element of namelist. 

nodename
Pointer to a caller-allocated buffer that holds a string, which clu_info() fills with the Connection Manager (CNX) node name of the specified member. 

sizeThe size of the member array, member_array. 

clu_gen_ptr
Address of a pointer to a structure of type struct clu_gen_info, which clu_get_info() will load with cluster information. (Use clu_free_info() to free the memory allocated for the structure.) 

clu_memb_ptr
Address of a pointer to a structure of type struct clu_member_info, which clu_get_memb_by_name() and clu_get_memb_by_id() will load with specific member information. (Use clu_free_memb() to free the memory allocated for the structure.) 

DESCRIPTION

When called from a member of a cluster, the clu_info() function returns specific cluster status information when the following options are specified:

       •CLU_INFO_MEMBSTATE − returns the following information about each cluster member’s state: up, down, or not configured. 

       •CLU_INFO_LIMITS − returns the following information on member IDs and supported members:

       —
Minimum supported member ID

       —
Maximum supported member ID

       —
Maximum supported number of members in a cluster

       •CLU_INFO_CLU_NAME − returns the cluster name. 

       •CLU_INFO_INTERNAME_BY_ID − returns the cluster interconnect host name given a specific member ID. 

       •CLU_INFO_INTERNAME_BY_NAME − returns the cluster interconnect host name given a specific host name. 

       •CLU_INFO_MEMBERID_BY_NAME − returns the member ID given a specific host name. 

       •CLU_INFO_HOSTNAME_BY_ID − returns the member host name given a specific member ID. 

       •CLU_INFO_NODENAME_BY_ID − returns the Connection Manager (CNX) node name given a specific member ID. 

       •CLU_INFO_NODENAME_BY_NAME − returns the CNX node name given a specific host name. 

       •CLU_INFO_MEMBLIST − returns a list of host names for all members in the cluster. 

       •CLU_INFO_MY_ID − returns the member ID for the member on which it is run. 

When called from a member of a cluster, the clu_get_info() function returns a structure containing general information about the cluster and its members. The information includes:

       •The name of the cluster and the number of members configured in the cluster. 

       •The device name and number of votes of the quorum disk, if configured. 

       •For each member, its member ID, host name, cluster interconnect IP name, and current state (UP or DOWN). 

When called from a system that is not a cluster member, the clu_get_info() function returns -1 (CLU_NOT_CONFIGURED). 

If a member of the cluster is down, or a member’s /etc/rc.config file contains illegal values, the values returned by string pointers can be NULL. 

Note that the clu_get_info function does not require allocated structures. While the clu_info function accepts pointers to caller-allocated structures, the clu_get_info function accepts a pointer to a structure. 

The clu_free_info() function frees the memory allocated for a clu_gen_info structure. The clu_gen_info structure is defined in <sys/clu.h>. 

Use the clu_get_memb_by_name() and clu_get_memb_by_id() functions to return information about a cluster member. The clu_get_memb_by_name() function returns a structure containing the host name of a cluster member, while the clu_get_memb_by_id() function returns a structure containing the member ID of a cluster member. 

The clu_free_memb() function frees the memory allocated for a clu_member_info structure. The clu_member_info structure is defined in <sys/clu.h>. 

RETURN VALUES

The clu_get_info() and clu_free_info() functions return one of the following values:

0Successful completion. 

CLU_NOT_CONFIGURED (-1)
System is not configured to be in a cluster.

CLU_NOT_MEMBER
Called from a system that is not a cluster member.

CLU_NO_MEMORY
There is no memory for the interface.

CLU_NO_MEMBERID
Cannot determine the value of the sysconfigtab memberid attribute. 

CLU_CNX_ERROR
Cannot query Connection Manager (CNX) subsystem.

EINVAL
The input to member_array is not large enough. 

The clu_info(), clu_get_memb_by_name(), clu_get_memb_by_id(), and clu_free_memb() functions return one of the following values:

0Successful completion. 

-1The operation was unsuccessful.  Check errno to determine the error. 

EXAMPLES

The following code fragments show typical calling sequences for the clu_info() options:

CLU_INFO_MEMBSTATE:

size_t size = 256;
char marray[256];
clu_info(CLU_INFO_MEMBSTATE, size, marray);

CLU_INFO_LIMITS:

struct clu_limits limits;
clu_info(CLU_INFO_LIMITS, &limits);

CLU_INFO_CLU_NAME:

char name[MAXHOSTNAMELEN];
clu_info(CLU_INFO_CLU_NAME, name, sizeof(name));

CLU_INFO_INTERNAME_BY_ID:

memberid_t memberid = 2;
char intername[MAXHOSTNAMELEN];
clu_info(CLU_INFO_INTERNAME_BY_ID, memberid, intername, sizeof(intername));

CLU_INFO_INTERNAME_BY_NAME:

char ∗hostname = "my_member";
char intername[MAXHOSTNAMELEN];
clu_info(CLU_INFO_INTERNAME_BY_NAME, hostname, intername, sizeof(intername));

CLU_INFO_MEMBERID_BY_NAME:

char ∗hostname = "my_member";
memberid_t memberid_out;
clu_info(CLU_INFO_MEMBERID_BY_NAME, hostname, &memberid_out);

CLU_INFO_HOSTNAME_BY_ID:

memberid_t memberid = 2;
char hostname_out[MAXHOSTNAMELEN];
clu_info(CLU_INFO_HOSTNAME_BY_ID, memberid, hostname_out, sizeof(hostname_out));

CLU_INFO_NODENAME_BY_ID:

memberid_t memberid = 2;
char nodename[MAXHOSTNAMELEN];
clu_info(CLU_INFO_NODENAME_BY_ID, memberid, nodename, sizeof(nodename));

CLU_INFO_NODENAME_BY_NAME:

char ∗hostname = "my_member";
char nodename[MAXHOSTNAMELEN];
clu_info(CLU_INFO_NODENAME_BY_NAME, hostname, nodename, sizeof(nodename));

CLU_INFO_MEMBLIST:

struct clu_limits limits;
char ∗∗namelist;
size_t size;
int i;
clu_info(CLU_INFO_LIMITS, &limits);
size = limits.max_membid;
namelist = (char ∗∗)calloc(size,sizeof(char ∗));
for(i=0;i<size;i++) {
    namelist[i] = (char ∗)calloc(MAXHOSTNAMELEN,sizeof(char));
    namelist[i][0] = ’ ’;
}
clu_info(CLU_INFO_MEMBLIST, namelist, &size, MAXHOSTNAMELEN);

CLU_INFO_MY_ID:

memberid_t my_memberid;
clu_info(CLU_INFO_MY_ID, &my_memberid);

The following code fragment shows a typical calling sequence for the clu_get_info() function:

#include <sys/clu.h>
int retval = 0;
int i = 0;
struct clu_gen_info ∗clugenptr;
clugenptr = NULL;
retval = clu_get_info(&clugenptr);
switch (retval) {
    case 0: break;
    case CLU_NOT_MEMBER:
    case CLU_NO_CLUSTER_NAME:
    case CLU_NO_MEMBERID:
    case CLU_CNX_ERROR:
      fprintf(stderr, "clu_get_info error0);
      exit(1);
    default:
      exit(1);
    }
if (clugenptr == NULL)
    exit(1);
for (i = 0; i <= clugenptr->clu_num_of_members -1; i++) {
    /∗ print or use the returned info; for example: ∗/
    printf("member hostname is %s0, clugenptr->memblist[i].hostname);
    }
clu_free_info(&clugenptr);

The following code fragment shows a typical calling sequence for the clu_get_memb_by_id() function (clu_get_memb_by_name() is similar):

#include <sys/clu.h>
#include <errno.h>
memberid_t memberid = 2;
struct clu_member_info ∗membinfo = NULL;
if (clu_get_memb_by_id(2, &membinfo)) {
    fprintf(stderr, "Error! Return code of %d0, errno);
    exit(1);
}
printf("Member cluster version is %s0, membinfo->clu_version);
clu_free_memb(&membinfo);

FILES

/etc/rc.config
Run-time configuration file for each cluster member.

SEE ALSO

Commands: clu_get_info(8)

Files: rc.config(8)