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Add MASTER REGISTER and STANDBY REGISTER commands.

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This commit is contained in:
Jaime Casanova
2010-10-18 02:21:55 -05:00
parent 6779a96b0b
commit 378bdd7bd4
6 changed files with 427 additions and 111 deletions
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24
README
View File

@@ -33,6 +33,16 @@ a port different then the default 5432 you can specify a -p parameter.
Standby is always considered as localhost and a second -p parameter will indicate
its port if is different from the default one.
* master register
Registers a master in a cluster, it needs to be executed before any node is
registered
* standby register
Registers a standby in a cluster, it needs to be executed before any repmgrd
is executed
* standby clone [node to be cloned]
Backup via rsync the data directory of the primary. And creates the recovery file
@@ -128,5 +138,17 @@ REPMGR DAEMON
=============
It reads the repmgr.conf file in current directory or as indicated with -f
parameter looks if the standby is in repl_nodes and if it is no
parameter looks if the standby is in repl_nodes and if it is not add it.
Before you can run the repmgr daemon (repmgrd) you need to register a master
and at least a standby in a cluster, for that you need to use the MASTER
REGISTER and STANDBY REGISTER commands.
For example, following last example and assuming that repmgr.conf is in postgres
home directory you will run this on the master:
repmgr -f /home/postgres/repmgr.conf master register
and the same in the standby.
The repmgr daemon creates 2 connections: one to master and other to standby.

80
dbutils.c
View File

@@ -128,3 +128,83 @@ get_cluster_size(PGconn *conn)
PQclear(res);
return size;
}
/*
* get a connection to master by reading repl_nodes, creating a connection
* to each node (one at a time) and finding if it is a master or a standby
*/
PGconn *
getMasterConnection(PGconn *standby_conn, int id, char *cluster, int *master_id)
{
PGconn *master_conn = NULL;
PGresult *res1;
PGresult *res2;
char sqlquery[8192];
char master_conninfo[8192];
int i;
/* find all nodes belonging to this cluster */
sprintf(sqlquery, "SELECT * FROM repmgr_%s.repl_nodes "
" WHERE cluster = '%s' and id <> %d",
cluster, cluster, id);
res1 = PQexec(standby_conn, sqlquery);
if (PQresultStatus(res1) != PGRES_TUPLES_OK)
{
fprintf(stderr, "Can't get nodes info: %s\n", PQerrorMessage(standby_conn));
PQclear(res1);
PQfinish(standby_conn);
exit(1);
}
for (i = 0; i < PQntuples(res1); i++)
{
/* initialize with the values of the current node being processed */
*master_id = atoi(PQgetvalue(res1, i, 0));
strcpy(master_conninfo, PQgetvalue(res1, i, 2));
master_conn = establishDBConnection(master_conninfo, false);
/*
* I can't use the is_standby() function here because on error that
* function closes the connection i pass and exit, but i still need to close
* standby_conn
*/
res2 = PQexec(master_conn, "SELECT pg_is_in_recovery()");
if (PQresultStatus(res2) != PGRES_TUPLES_OK)
{
fprintf(stderr, "Can't get nodes info: %s\n", PQerrorMessage(master_conn));
PQclear(res2);
PQfinish(master_conn);
continue;
}
/* if false, this is the master */
if (strcmp(PQgetvalue(res2, 0, 0), "f") == 0)
{
PQclear(res2);
PQclear(res1);
return master_conn;
}
else
{
/* if it is a standby clear info */
PQclear(res2);
PQfinish(master_conn);
*master_id = -1;
}
}
/* If we finish this loop without finding a master then
* we doesn't have the info or the master has failed (or we
* reached max_connections or superuser_reserved_connections,
* anything else i'm missing?),
* Probably we will need to check the error to know if we need
* to start failover procedure or just fix some situation on the
* standby.
*/
fprintf(stderr, "There isn't a master node in the cluster\n");
PQclear(res1);
PQfinish(master_conn);
return (PGconn *) NULL;
}

1
dbutils.h
View File

@@ -9,3 +9,4 @@ bool is_standby(PGconn *conn);
bool is_supported_version(PGconn *conn);
bool guc_setted(PGconn *conn, const char *parameter, const char *op, const char *value);
const char *get_cluster_size(PGconn *conn);
PGconn * getMasterConnection(PGconn *standby_conn, int id, char *cluster, int *master_id);

340
repmgr.c
View File

@@ -3,10 +3,12 @@
* Copyright (c) 2ndQuadrant, 2010
*
* Command interpreter for the repmgr
* This module execute some tasks based on commands and then exit
* This module is a command-line utility to easily setup a cluster of
* hot standby servers for an HA environment
*
* Commands implemented are.
* STANDBY CLONE, STANDBY FOLLOW, STANDBY PROMOTE
* MASTER REGISTER, STANDBY REGISTER, STANDBY CLONE, STANDBY FOLLOW,
* STANDBY PROMOTE
*/
#include "repmgr.h"
@@ -21,15 +23,19 @@
#define RECOVERY_FILE "recovery.conf"
#define RECOVERY_DONE_FILE "recovery.done"
#define STANDBY_NORMAL 0 /* Not a real action, just to initialize */
#define STANDBY_CLONE 1
#define STANDBY_PROMOTE 2
#define STANDBY_FOLLOW 3
#define NO_ACTION 0 /* Not a real action, just to initialize */
#define MASTER_REGISTER 1
#define STANDBY_REGISTER 2
#define STANDBY_CLONE 3
#define STANDBY_PROMOTE 4
#define STANDBY_FOLLOW 5
static void help(const char *progname);
static bool create_recovery_file(const char *data_dir);
static int copy_remote_files(char *host, char *remote_path, char *local_path, bool is_directory);
static void do_master_register(void);
static void do_standby_register(void);
static void do_standby_clone(void);
static void do_standby_promote(void);
static void do_standby_follow(void);
@@ -43,6 +49,7 @@ const char *dbname = NULL;
char *host = NULL;
char *username = NULL;
char *dest_dir = NULL;
char *config_file = NULL;
bool verbose = false;
bool force = false;
@@ -50,8 +57,8 @@ int numport = 0;
char *masterport = NULL;
char *standbyport = NULL;
char *stndby = NULL;
char *stndby_cmd = NULL;
char *server_mode = NULL;
char *server_cmd = NULL;
int
@@ -63,6 +70,7 @@ main(int argc, char **argv)
{"port", required_argument, NULL, 'p'},
{"username", required_argument, NULL, 'U'},
{"dest-dir", required_argument, NULL, 'D'},
{"config-file", required_argument, NULL, 'f'},
{"force", no_argument, NULL, 'F'},
{"verbose", no_argument, NULL, 'v'},
{NULL, 0, NULL, 0}
@@ -70,7 +78,7 @@ main(int argc, char **argv)
int optindex;
int c;
int action = STANDBY_NORMAL;
int action = NO_ACTION;
progname = get_progname(argv[0]);
@@ -89,7 +97,7 @@ main(int argc, char **argv)
}
while ((c = getopt_long(argc, argv, "d:h:p:U:D:Fv", long_options, &optindex)) != -1)
while ((c = getopt_long(argc, argv, "d:h:p:U:D:f:F:v", long_options, &optindex)) != -1)
{
switch (c)
{
@@ -119,6 +127,11 @@ main(int argc, char **argv)
case 'D':
dest_dir = optarg;
break;
case 'f':
config_file = optarg;
if (config_file == NULL)
sprintf(config_file, "./%s", CONFIG_FILE);
break;
case 'F':
force = true;
break;
@@ -132,16 +145,17 @@ main(int argc, char **argv)
}
/*
* Now we need to obtain the action, this comes in the form:
* STANDBY {CLONE [node]|PROMOTE|FOLLOW [node]}
* Now we need to obtain the action, this comes in one of these forms:
* MASTER REGISTER |
* STANDBY {REGISTER | CLONE [node] | PROMOTE | FOLLOW [node]}
*
* the node part is optional, if we receive it then we shouldn't
* have received a -h option
*/
if (optind < argc)
{
stndby = argv[optind++];
if (strcasecmp(stndby, "STANDBY") != 0)
server_mode = argv[optind++];
if (strcasecmp(server_mode, "STANDBY") != 0 && strcasecmp(server_mode, "MASTER") != 0)
{
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
exit(1);
@@ -150,12 +164,25 @@ main(int argc, char **argv)
if (optind < argc)
{
stndby_cmd = argv[optind++];
if (strcasecmp(stndby_cmd, "CLONE") == 0)
server_cmd = argv[optind++];
if (strcasecmp(server_cmd, "REGISTER") == 0)
{
/*
* we don't use this info in any other place so i will
* just execute the compare again instead of having an
* additional variable to hold a value that we will use
* no more
*/
if (strcasecmp(server_mode, "MASTER") == 0)
action = MASTER_REGISTER;
else if (strcasecmp(server_mode, "STANDBY") == 0)
action = STANDBY_REGISTER;
}
else if (strcasecmp(server_cmd, "CLONE") == 0)
action = STANDBY_CLONE;
else if (strcasecmp(stndby_cmd, "PROMOTE") == 0)
else if (strcasecmp(server_cmd, "PROMOTE") == 0)
action = STANDBY_PROMOTE;
else if (strcasecmp(stndby_cmd, "FOLLOW") == 0)
else if (strcasecmp(server_cmd, "FOLLOW") == 0)
action = STANDBY_FOLLOW;
else
{
@@ -164,8 +191,9 @@ main(int argc, char **argv)
}
}
/* For STANDBY CLONE and STANDBY FOLLOW we still can receive a last argument */
if ((action == STANDBY_CLONE) || (action == STANDBY_FOLLOW))
/* For some actions we still can receive a last argument */
if ((action == STANDBY_CLONE) || (action == STANDBY_FOLLOW) ||
(action == MASTER_REGISTER) || (action == STANDBY_REGISTER))
{
if (optind < argc)
{
@@ -213,6 +241,12 @@ main(int argc, char **argv)
switch (action)
{
case MASTER_REGISTER:
do_master_register();
break;
case STANDBY_REGISTER:
do_standby_register();
break;
case STANDBY_CLONE:
do_standby_clone();
break;
@@ -231,6 +265,266 @@ main(int argc, char **argv)
}
static void
do_master_register(void)
{
PGconn *conn;
PGresult *res;
char sqlquery[8192];
char myClusterName[MAXLEN];
int myLocalId = -1;
char conninfo[MAXLEN];
bool schema_exists = false;
/*
* Read the configuration file: repmgr.conf
*/
parse_config(config_file, myClusterName, &myLocalId, conninfo);
if (myLocalId == -1)
{
fprintf(stderr, "Node information is missing. "
"Check the configuration file.\n");
exit(1);
}
conn = establishDBConnection(conninfo, true);
/* Check we are a master */
if (is_standby(conn))
{
fprintf(stderr, "repmgr: This node should be a master\n");
PQfinish(conn);
return;
}
/* Check if there is a schema for this cluster */
sprintf(sqlquery, "SELECT 1 FROM pg_namespace WHERE nspname = 'repmgr_%s'", myClusterName);
res = PQexec(conn, sqlquery);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
fprintf(stderr, "Can't get info about schemas: %s\n", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return;
}
if (!PQgetisnull(res, 0, 0)) /* schema exists */
{
if (!force) /* and we are not forcing so error */
{
fprintf(stderr, "Schema repmgr_%s already exists.", myClusterName);
PQclear(res);
PQfinish(conn);
return;
}
schema_exists = true;
}
PQclear(res);
if (!schema_exists)
{
/* ok, create the schema */
sprintf(sqlquery, "CREATE SCHEMA repmgr_%s", myClusterName);
if (!PQexec(conn, sqlquery))
{
fprintf(stderr, "Cannot create the schema repmgr_%s: %s\n",
myClusterName, PQerrorMessage(conn));
PQfinish(conn);
return;
}
/* ... the tables */
sprintf(sqlquery, "CREATE TABLE repmgr_%s.repl_nodes ( "
" id integer primary key, "
" cluster text not null, "
" conninfo text not null)", myClusterName);
if (!PQexec(conn, sqlquery))
{
fprintf(stderr, "Cannot create the table repmgr_%s.repl_nodes: %s\n",
myClusterName, PQerrorMessage(conn));
PQfinish(conn);
return;
}
sprintf(sqlquery, "CREATE TABLE repmgr_%s.repl_monitor ( "
" primary_node INTEGER NOT NULL, "
" standby_node INTEGER NOT NULL, "
" last_monitor_time TIMESTAMP WITH TIME ZONE NOT NULL, "
" last_wal_primary_location TEXT NOT NULL, "
" last_wal_standby_location TEXT NOT NULL, "
" replication_lag BIGINT NOT NULL, "
" apply_lag BIGINT NOT NULL) ", myClusterName);
if (!PQexec(conn, sqlquery))
{
fprintf(stderr, "Cannot create the table repmgr_%s.repl_monitor: %s\n",
myClusterName, PQerrorMessage(conn));
PQfinish(conn);
return;
}
/* and the view */
sprintf(sqlquery, "CREATE VIEW repmgr_%s.repl_status AS "
" WITH monitor_info AS (SELECT *, ROW_NUMBER() OVER (PARTITION BY primary_node, standby_node "
" ORDER BY last_monitor_time desc) "
" FROM repmgr_%s.repl_monitor) "
" SELECT primary_node, standby_node, last_monitor_time, last_wal_primary_location, "
" last_wal_standby_location, pg_size_pretty(replication_lag) replication_lag, "
" pg_size_pretty(apply_lag) apply_lag, age(now(), last_monitor_time) AS time_lag "
" FROM monitor_info a "
" WHERE row_number = 1", myClusterName, myClusterName);
if (!PQexec(conn, sqlquery))
{
fprintf(stderr, "Cannot create the view repmgr_%s.repl_status: %s\n",
myClusterName, PQerrorMessage(conn));
PQfinish(conn);
return;
}
}
else
{
PGconn *master_conn;
int id;
/* Ensure there isn't any other master already registered */
master_conn = getMasterConnection(conn, myLocalId, myClusterName, &id);
if (master_conn != NULL)
{
PQfinish(master_conn);
fprintf(stderr, "There is a master already in this cluster");
return;
}
}
/* Now register the master */
if (force)
{
sprintf(sqlquery, "DELETE FROM repmgr_%s.repl_nodes "
" WHERE id = %d",
myClusterName, myLocalId);
if (!PQexec(conn, sqlquery))
{
fprintf(stderr, "Cannot delete node details, %s\n",
PQerrorMessage(conn));
PQfinish(conn);
return;
}
}
sprintf(sqlquery, "INSERT INTO repmgr_%s.repl_nodes "
"VALUES (%d, '%s', '%s')",
myClusterName, myLocalId, myClusterName, conninfo);
if (!PQexec(conn, sqlquery))
{
fprintf(stderr, "Cannot insert node details, %s\n",
PQerrorMessage(conn));
PQfinish(conn);
return;
}
PQfinish(conn);
return;
}
static void
do_standby_register(void)
{
PGconn *conn;
PGconn *master_conn;
int master_id;
PGresult *res;
char sqlquery[8192];
char myClusterName[MAXLEN];
int myLocalId = -1;
char conninfo[MAXLEN];
/*
* Read the configuration file: repmgr.conf
*/
parse_config(config_file, myClusterName, &myLocalId, conninfo);
if (myLocalId == -1)
{
fprintf(stderr, "Node information is missing. "
"Check the configuration file.\n");
exit(1);
}
conn = establishDBConnection(conninfo, true);
/* Check we are a standby */
if (!is_standby(conn))
{
fprintf(stderr, "repmgr: This node should be a standby\n");
PQfinish(conn);
return;
}
/* Check if there is a schema for this cluster */
sprintf(sqlquery, "SELECT 1 FROM pg_namespace WHERE nspname = 'repmgr_%s'", myClusterName);
res = PQexec(conn, sqlquery);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
fprintf(stderr, "Can't get info about tablespaces: %s\n", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return;
}
if (PQgetisnull(res, 0, 0)) /* schema doesn't exists */
{
fprintf(stderr, "Schema repmgr_%s doesn't exists.", myClusterName);
PQclear(res);
PQfinish(conn);
return;
}
PQclear(res);
master_conn = getMasterConnection(conn, myLocalId, myClusterName, &master_id);
if (!master_conn)
return;
/* Now register the standby */
if (force)
{
sprintf(sqlquery, "DELETE FROM repmgr_%s.repl_nodes "
" WHERE id = %d",
myClusterName, myLocalId);
if (!PQexec(master_conn, sqlquery))
{
fprintf(stderr, "Cannot delete node details, %s\n",
PQerrorMessage(master_conn));
PQfinish(master_conn);
PQfinish(conn);
return;
}
}
sprintf(sqlquery, "INSERT INTO repmgr_%s.repl_nodes "
"VALUES (%d, '%s', '%s')",
myClusterName, myLocalId, myClusterName, conninfo);
if (!PQexec(master_conn, sqlquery))
{
fprintf(stderr, "Cannot insert node details, %s\n",
PQerrorMessage(master_conn));
PQfinish(master_conn);
PQfinish(conn);
return;
}
PQfinish(master_conn);
PQfinish(conn);
return;
}
static void
do_standby_clone(void)
{
@@ -238,7 +532,7 @@ do_standby_clone(void)
PGresult *res;
char sqlquery[8192];
int r;
int r = 0;
int i;
bool pg_dir = false;
char master_data_directory[MAXLEN];
@@ -783,10 +1077,12 @@ help(const char *progname)
printf(_(" -h, --host=HOSTNAME database server host or socket directory\n"));
printf(_(" -p, --port=PORT database server port\n"));
printf(_(" -U, --username=USERNAME user name to connect as\n"));
printf(_(" -D, --data-dir=DIR directory where the files will be copied to\n"));
printf(_(" -D, --data-dir=DIR directory where the files will be copied to\n"));
printf(_("\n%s performs some tasks like clone a node, promote it "), progname);
printf(_("or making follow another node and then exits.\n"));
printf(_("COMMANDS:\n"));
printf(_(" master register - registers the master in a cluster\n"));
printf(_(" standby register - registers a standby in a cluster\n"));
printf(_(" standby clone [node] - allows creation of a new standby\n"));
printf(_(" standby promote - allows manual promotion of a specific standby into a "));
printf(_("new master in the event of a failover\n"));

6
repmgr.sql
View File

@@ -1,7 +1,5 @@
CREATE USER repmgr;
CREATE DATABASE repmgr OWNER repmgr;
\c repmgr
CREATE SCHEMA repmgr;
/*
* The table repl_nodes keeps information about all machines in
@@ -40,7 +38,7 @@ ALTER TABLE repl_monitor OWNER TO repmgr;
* apply_lag: in bytes (this is how far the latest xlog record
* we have applied is from the latest record we
* have received)
* time-lag: how many seconds are we from being up-to-date with master
* time_lag: how many seconds are we from being up-to-date with master
*/
drop view if exists repl_status;
CREATE VIEW repl_status AS

87
repmgrd.c
View File

@@ -40,7 +40,6 @@ bool verbose = false;
static void help(const char *progname);
static void checkClusterConfiguration(void);
static void checkNodeConfiguration(char *conninfo);
static void getPrimaryConnection(void);
static void CancelQuery(void);
static void MonitorExecute(void);
@@ -148,7 +147,9 @@ main(int argc, char **argv)
else
{
/* I need the id of the primary as well as a connection to it */
getPrimaryConnection();
primaryConn = getMasterConnection(myLocalConn, myLocalId, myClusterName, &primaryId);
if (primaryConn == NULL)
exit(1);
}
checkClusterConfiguration();
@@ -165,88 +166,6 @@ main(int argc, char **argv)
}
/*
* get a connection to primary by reading repl_nodes, creating a connection
* to each node (one at a time) and finding if it is a primary or a standby
*/
static void
getPrimaryConnection(void)
{
PGresult *res1;
PGresult *res2;
int i;
/* find all nodes belonging to this cluster */
sprintf(sqlquery, "SELECT * FROM repl_nodes "
" WHERE cluster = '%s' and id <> %d",
myClusterName, myLocalId);
res1 = PQexec(myLocalConn, sqlquery);
if (PQresultStatus(res1) != PGRES_TUPLES_OK)
{
fprintf(stderr, "Can't get nodes info: %s\n", PQerrorMessage(myLocalConn));
PQclear(res1);
CloseConnections();
exit(1);
}
for (i = 0; i < PQntuples(res1); i++)
{
/* initialize with the values of the current node being processed */
primaryId = atoi(PQgetvalue(res1, i, 0));
strcpy(primaryConninfo, PQgetvalue(res1, i, 2));
primaryConn = establishDBConnection(primaryConninfo, false);
/*
* I can't use the is_standby() function here because on error that
* function closes the one i pass and exit, but i still need to close
* myLocalConn
*/
res2 = PQexec(primaryConn, "SELECT pg_is_in_recovery()");
if (PQresultStatus(res2) != PGRES_TUPLES_OK)
{
fprintf(stderr, "Can't get nodes info: %s\n", PQerrorMessage(primaryConn));
PQclear(res1);
PQclear(res2);
CloseConnections();
exit(1);
}
/* if false, this is the primary */
if (strcmp(PQgetvalue(res2, 0, 0), "f") == 0)
{
PQclear(res2);
PQclear(res1);
/* We turn off synchronous_commit for the monitor info inserts */
res1 = PQexec(primaryConn, "SET synchronous_commit TO off");
PQclear(res1);
return;
}
else
{
/* if it is a standby clear info */
PQclear(res2);
PQfinish(primaryConn);
primaryId = -1;
}
}
/* If we finish this loop without finding a primary then
* we doesn't have the info or the primary has failed (or we
* reached max_connections or superuser_reserved_connections,
* anything else i'm missing?),
* Probably we will need to check the error to know if we need
* to start failover procedure or just fix some situation on the
* standby.
*/
fprintf(stderr, "There isn't a primary node the cluster\n");
PQclear(res1);
CloseConnections();
exit(1);
}
/*
* Insert monitor info, this is basically the time and xlog replayed,
* applied on standby and current xlog location in primary.