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Support pg_rewind when executing "repmgr standby switchover"

Browse Source 
9.5 and later.
This commit is contained in:
Ian Barwick
2016-01-20 13:05:47 +09:00
parent f982708b35
commit 211768d911
2 changed files with 386 additions and 31 deletions
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413
repmgr.c
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@@ -21,6 +21,10 @@
* CLUSTER SHOW
* CLUSTER CLEANUP
*
* For internal use:
* STANDBY ARCHIVE-CONFIG
* STANDBY RESTORE-CONFIG
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
@@ -38,8 +42,11 @@
#include "repmgr.h"
#include <sys/types.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
@@ -70,10 +77,11 @@
#define STANDBY_PROMOTE 5
#define STANDBY_FOLLOW 6
#define STANDBY_SWITCHOVER 7
#define WITNESS_CREATE 8
#define CLUSTER_SHOW 9
#define CLUSTER_CLEANUP 10
#define STANDBY_ARCHIVE_CONFIG 8
#define STANDBY_RESTORE_CONFIG 9
#define WITNESS_CREATE 10
#define CLUSTER_SHOW 11
#define CLUSTER_CLEANUP 12
static bool create_recovery_file(const char *data_dir);
@@ -99,6 +107,8 @@ static void do_standby_clone(void);
static void do_standby_promote(void);
static void do_standby_follow(void);
static void do_standby_switchover(void);
static void do_standby_archive_config(void);
static void do_standby_restore_config(void);
static void do_witness_create(void);
static void do_cluster_show(void);
static void do_cluster_cleanup(void);
@@ -110,6 +120,7 @@ static void help(void);
static bool remote_command(const char *host, const char *user, const char *command, PQExpBufferData *outputbuf);
static void format_db_cli_params(const char *conninfo, char *output);
static bool copy_file(const char *old_filename, const char *new_filename);
/* Global variables */
static const char *keywords[6];
@@ -166,6 +177,7 @@ main(int argc, char **argv)
{"check-upstream-config", no_argument, NULL, 2},
{"recovery-min-apply-delay", required_argument, NULL, 3},
{"ignore-external-config-files", no_argument, NULL, 4},
{"config-archive-dir", required_argument, NULL, 5},
{"help", no_argument, NULL, '?'},
{"version", no_argument, NULL, 'V'},
{NULL, 0, NULL, 0}
@@ -339,6 +351,9 @@ main(int argc, char **argv)
case 4:
runtime_options.ignore_external_config_files = true;
break;
case 5:
strncpy(runtime_options.config_archive_dir, optarg, MAXLEN);
break;
default:
{
@@ -367,8 +382,8 @@ main(int argc, char **argv)
/*
* Now we need to obtain the action, this comes in one of these forms:
* MASTER REGISTER |
* STANDBY {REGISTER | UNREGISTER | CLONE [node] | PROMOTE | FOLLOW [node] | SWITCHOVER} |
* { MASTER | PRIMARY } REGISTER |
* STANDBY {REGISTER | UNREGISTER | CLONE [node] | PROMOTE | FOLLOW [node] | SWITCHOVER | REWIND} |
* WITNESS CREATE |
* CLUSTER {SHOW | CLEANUP}
*
@@ -415,6 +430,10 @@ main(int argc, char **argv)
action = STANDBY_FOLLOW;
else if (strcasecmp(server_cmd, "SWITCHOVER") == 0)
action = STANDBY_SWITCHOVER;
else if (strcasecmp(server_cmd, "ARCHIVE-CONFIG") == 0)
action = STANDBY_ARCHIVE_CONFIG;
else if (strcasecmp(server_cmd, "RESTORE-CONFIG") == 0)
action = STANDBY_RESTORE_CONFIG;
}
else if (strcasecmp(server_mode, "CLUSTER") == 0)
{
@@ -646,6 +665,12 @@ main(int argc, char **argv)
case STANDBY_SWITCHOVER:
do_standby_switchover();
break;
case STANDBY_ARCHIVE_CONFIG:
do_standby_archive_config();
break;
case STANDBY_RESTORE_CONFIG:
do_standby_restore_config();
break;
case WITNESS_CREATE:
do_witness_create();
break;
@@ -2163,7 +2188,6 @@ do_standby_follow(void)
log_debug("do_standby_follow()\n");
/*
* If -h/--host wasn't provided, attempt to connect to standby
* to determine primary, and carry out some other checks while we're
@@ -2374,6 +2398,8 @@ do_standby_switchover(void)
{
PGconn *local_conn;
PGconn *remote_conn;
int server_version_num;
bool use_pg_rewind;
/* the remote server is the primary which will be demoted */
char remote_conninfo[MAXCONNINFO] = "";
@@ -2381,6 +2407,7 @@ do_standby_switchover(void)
char remote_data_directory[MAXLEN];
int remote_node_id;
char remote_node_replication_state[MAXLEN] = "";
char remote_archive_config_dir[MAXLEN];
int i,
r = 0;
@@ -2406,6 +2433,8 @@ do_standby_switchover(void)
exit(ERR_BAD_CONFIG);
}
server_version_num = check_server_version(local_conn, "master", true, NULL);
/*
* TODO: check that standby's upstream node is the primary
* (it's probably not feasible to switch over to a cascaded standby)
@@ -2422,6 +2451,19 @@ do_standby_switchover(void)
exit(ERR_DB_CON);
}
/* Get the remote's node record */
query_result = get_node_record(remote_conn, options.cluster_name, remote_node_id, &remote_node_record);
if (query_result < 1)
{
log_err(_("unable to retrieve node record for node %i\n"), remote_node_id);
PQfinish(local_conn);
exit(ERR_DB_QUERY);
}
log_debug("remote node name is \"%s\"\n", remote_node_record.name);
/*
* Check that we can connect by SSH to the remote (current primary) server,
* and read its data directory
@@ -2449,7 +2491,7 @@ do_standby_switchover(void)
exit(ERR_DB_CON);
}
log_debug("primary's data directory is: %s\n", remote_data_directory);
log_debug("master's data directory is: %s\n", remote_data_directory);
maxlen_snprintf(command,
"ls %s/PG_VERSION >/dev/null 2>&1 && echo 1 || echo 0",
@@ -2576,6 +2618,46 @@ do_standby_switchover(void)
}
}
if (server_version_num >= 90500)
{
use_pg_rewind = true;
}
// elseif (server_version_num < 90500) && --pg_rewind supplied
// - check found
/*
* When using pg_rewind (the preferable option), we need to
* archive any configuration files in the remote server's
* data directory as they'll be overwritten by pg_rewind
*/
if (use_pg_rewind == true)
{
maxlen_snprintf(remote_archive_config_dir,
"/tmp/repmgr-%s-archive",
remote_node_record.name);
log_verbose(LOG_DEBUG, "remote_archive_config_dir: %s\n", remote_archive_config_dir);
maxlen_snprintf(command,
"%s/repmgr standby archive-config -f %s --config-archive-dir=%s",
pg_bindir,
runtime_options.remote_config_file,
remote_archive_config_dir);
log_debug("Executing:\n%s\n", command);
initPQExpBuffer(&command_output);
(void)remote_command(
remote_host,
runtime_options.remote_user,
command,
&command_output);
termPQExpBuffer(&command_output);
}
/*
* Stop the remote primary
*
@@ -2622,7 +2704,7 @@ do_standby_switchover(void)
{
/* Check whether primary is available */
remote_conn = establish_db_connection(remote_conninfo, false); /* don't fail on error */
remote_conn = test_db_connection(remote_conninfo, false); /* don't fail on error */
/* XXX failure to connect doesn't mean the server is necessarily
* completely stopped - we need to better detect the reason for
@@ -2634,7 +2716,7 @@ do_standby_switchover(void)
{
connection_success = true;
log_notice(_("current primary has been stopped"));
log_notice(_("current master has been stopped"));
break;
}
PQfinish(remote_conn);
@@ -2646,8 +2728,8 @@ do_standby_switchover(void)
if (connection_success == false)
{
log_err(_("primary server did not shut down\n"));
log_hint(_("check the primary server status before performing any further actions"));
log_err(_("master server did not shut down\n"));
log_hint(_("check the master server status before performing any further actions"));
exit(ERR_FAILOVER_FAIL);
}
@@ -2665,6 +2747,51 @@ do_standby_switchover(void)
/* TODO: additional check old primary is shut down */
if (use_pg_rewind == true)
{
/* Execute pg_rewind */
maxlen_snprintf(command,
"%s/pg_rewind -D %s --source-server=\\'%s\\'",
pg_bindir,
remote_data_directory,
options.conninfo);
log_debug("Executing:\n%s\n", command);
initPQExpBuffer(&command_output);
// XXX handle failure
(void)remote_command(
remote_host,
runtime_options.remote_user,
command,
&command_output);
termPQExpBuffer(&command_output);
/* Restore any previously archived config files */
maxlen_snprintf(command,
"%s/repmgr standby restore-config -D %s --config-archive-dir=%s",
pg_bindir,
remote_data_directory,
remote_archive_config_dir);
initPQExpBuffer(&command_output);
// XXX handle failure
(void)remote_command(
remote_host,
runtime_options.remote_user,
command,
&command_output);
termPQExpBuffer(&command_output);
/* XXX remove any recovery.done file copied in by pg_rewind */
}
format_db_cli_params(options.conninfo, repmgr_db_cli_params);
maxlen_snprintf(command,
"%s/repmgr -D %s -f %s %s standby follow",
@@ -2672,7 +2799,7 @@ do_standby_switchover(void)
remote_data_directory,
runtime_options.remote_config_file,
repmgr_db_cli_params
);
);
log_debug("Executing:\n%s\n", command);
@@ -2688,7 +2815,6 @@ do_standby_switchover(void)
termPQExpBuffer(&command_output);
/* verify that new standby is connected and replicating */
connection_success = false;
@@ -2697,14 +2823,14 @@ do_standby_switchover(void)
{
/* Check whether primary is available */
remote_conn = establish_db_connection(remote_conninfo, false); /* don't fail on error */
remote_conn = test_db_connection(remote_conninfo, false); /* don't fail on error */
if (PQstatus(remote_conn) == CONNECTION_OK)
{
log_debug("connected to new standby (old primary)\n");
log_debug("connected to new standby (old master)\n");
if (is_standby(remote_conn) == 0)
{
log_err(_("new standby (old primary) is not a standby\n"));
log_err(_("new standby (old master) is not a standby\n"));
exit(ERR_FAILOVER_FAIL);
}
connection_success = true;
@@ -2718,7 +2844,7 @@ do_standby_switchover(void)
if (connection_success == false)
{
log_err(_("unable to connect to new standby (old primary)\n"));
log_err(_("unable to connect to new standby (old master)\n"));
exit(ERR_FAILOVER_FAIL);
}
@@ -2727,17 +2853,7 @@ do_standby_switchover(void)
/* Check for entry in pg_stat_replication */
local_conn = establish_db_connection(options.conninfo, true);
query_result = get_node_record(local_conn, options.cluster_name, remote_node_id, &remote_node_record);
if (query_result < 1)
{
// XXX error message
PQfinish(local_conn);
exit(ERR_DB_QUERY);
}
log_debug("remote node name is \"%s\"\n", remote_node_record.name);
query_result = get_node_replication_state(local_conn, remote_node_record.name, remote_node_replication_state);
if (query_result == -1)
@@ -2756,6 +2872,7 @@ do_standby_switchover(void)
else
{
/* XXX other valid values? */
/* XXX we should poll for a while in case the node takes time to connect to the primary */
if (strcmp(remote_node_replication_state, "streaming") == 0 ||
strcmp(remote_node_replication_state, "catchup") == 0)
{
@@ -2786,7 +2903,7 @@ do_standby_switchover(void)
if (PQstatus(remote_conn) != CONNECTION_OK)
{
log_warning(_("unable to connect to former primary to clean up replication slots \n"));
log_warning(_("unable to connect to former master to clean up replication slots \n"));
}
else
{
@@ -2828,6 +2945,184 @@ do_standby_switchover(void)
}
/*
* Intended mainly for "internal" use by `standby switchover`, which
* calls this on the target server to archive any configuration files
* in the data directory, which may be overwritten by an operation
* like pg_rewind
*/
static void
do_standby_archive_config(void)
{
PGconn *local_conn = NULL;
char sqlquery[QUERY_STR_LEN];
PGresult *res;
int i, copied_count = 0;
if (mkdir(runtime_options.config_archive_dir, S_IRWXU) != 0 && errno != EEXIST)
{
log_err(_("unable to create temporary directory\n"));
exit(ERR_BAD_CONFIG);
}
// XXX check if directory is directory and we own it
// XXX delete any files in dir in case it existed already
local_conn = establish_db_connection(options.conninfo, true);
/*
* Detect which config files are actually inside the data directory;
* this query will include any settings from included files too
*/
sqlquery_snprintf(sqlquery,
"WITH files AS ( "
" WITH dd AS ( "
" SELECT setting "
" FROM pg_settings "
" WHERE name = 'data_directory') "
" SELECT distinct(sourcefile) AS config_file"
" FROM dd, pg_settings ps "
" WHERE ps.sourcefile IS NOT NULL "
" AND ps.sourcefile ~ ('^' || dd.setting) "
" UNION "
" SELECT ps.setting AS config_file"
" FROM dd, pg_settings ps "
" WHERE ps.name IN ( 'config_file', 'hba_file', 'ident_file') "
" AND ps.setting ~ ('^' || dd.setting) "
") "
" SELECT config_file, "
" regexp_replace(config_file, '^.*\\/','') AS filename "
" FROM files "
"ORDER BY config_file");
log_verbose(LOG_DEBUG, "do_standby_archive_config(): %s\n", sqlquery);
res = PQexec(local_conn, sqlquery);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
log_err(_("unable to query config file locations\n"));
PQclear(res);
PQfinish(local_conn);
exit(ERR_DB_QUERY);
}
/* Copy any configuration files to the specified directory */
for (i = 0; i < PQntuples(res); i++)
{
PQExpBufferData buf;
initPQExpBuffer(&buf);
appendPQExpBuffer(&buf, "%s/%s",
runtime_options.config_archive_dir, PQgetvalue(res, i, 1));
log_verbose(LOG_DEBUG, "Copying %s to %s/\n", PQgetvalue(res, i, 0), buf.data);
/* XXX check result */
copy_file(PQgetvalue(res, i, 0), buf.data);
termPQExpBuffer(&buf);
copied_count++;
}
PQclear(res);
PQfinish(local_conn);
log_notice(_("%i files copied to %s\n"), copied_count, runtime_options.config_archive_dir);
}
/*
* Intended mainly for "internal" use by `standby switchover`, which
* calls this on the target server to restore any configuration files
* to the data directory, which may have been overwritten by an operation
* like pg_rewind
*
* Not designed to be called if the instance is running, but does
* not currently check.
*
* Requires -D/--data-dir and --config_archive_dir
*
* Removes --config_archive_dir after successful copy
*/
static void
do_standby_restore_config(void)
{
DIR *arcdir;
struct dirent *arcdir_ent;
int copied_count = 0;
bool copy_ok = true;
arcdir = opendir(runtime_options.config_archive_dir);
if (arcdir == NULL)
{
log_err(_("Unable to open directory '%s'\n"), runtime_options.config_archive_dir);
exit(ERR_BAD_CONFIG);
}
while ((arcdir_ent = readdir(arcdir)) != NULL) {
PQExpBufferData src_file;
PQExpBufferData dst_file;
if (arcdir_ent->d_type != DT_REG)
{
continue;
}
initPQExpBuffer(&src_file);
initPQExpBuffer(&dst_file);
appendPQExpBuffer(&src_file, "%s/%s",
runtime_options.config_archive_dir, arcdir_ent->d_name);
appendPQExpBuffer(&dst_file, "%s/%s",
runtime_options.dest_dir, arcdir_ent->d_name);
log_verbose(LOG_DEBUG, "Copying %s to %s\n", src_file.data, dst_file.data);
/* XXX check result */
if (copy_file(src_file.data, dst_file.data) == false)
{
copy_ok = false;
log_warning(_("Unable to copy %s from %s\n"), arcdir_ent->d_name, runtime_options.config_archive_dir);
}
else
{
unlink(src_file.data);
copied_count++;
}
termPQExpBuffer(&src_file);
termPQExpBuffer(&dst_file);
}
closedir(arcdir);
if (copy_ok == false)
{
log_err(_("Unable to copy all files from %s\n"), runtime_options.config_archive_dir);
exit(ERR_BAD_CONFIG);
}
log_notice(_("%i files copied to %s\n"), copied_count, runtime_options.dest_dir);
/*
* Finally, delete directory - it should be empty unless it's been interfered
* with for some reason, in which case manual attention is required
*/
if (rmdir(runtime_options.config_archive_dir) != 0 && errno != EEXIST)
{
log_err(_("Unable to delete %s\n"), runtime_options.config_archive_dir);
exit(ERR_BAD_CONFIG);
}
log_verbose(LOG_NOTICE, "Directory %s deleted\n", runtime_options.config_archive_dir);
return;
}
static void
do_witness_create(void)
{
@@ -3743,13 +4038,32 @@ check_parameters_for_action(const int action)
}
if (runtime_options.fast_checkpoint && runtime_options.rsync_only)
{
error_list_append(&cli_warnings, _("-c/--fast-checkpoint has no effect when using -r/--rsync-only "));
error_list_append(&cli_warnings, _("-c/--fast-checkpoint has no effect when using -r/--rsync-only "));
}
config_file_required = false;
break;
case STANDBY_SWITCHOVER:
/* allow all parameters to be supplied */
break;
case STANDBY_ARCHIVE_CONFIG:
if (strcmp(runtime_options.config_archive_dir, "") == 0)
{
error_list_append(&cli_errors, _("--config-archive-dir required when executing STANDBY ARCHIVE_CONFIG"));
}
break;
case STANDBY_RESTORE_CONFIG:
if (strcmp(runtime_options.config_archive_dir, "") == 0)
{
error_list_append(&cli_errors, _("--config-archive-dir required when executing STANDBY RESTORE_CONFIG"));
}
if (strcmp(runtime_options.dest_dir, "") == 0)
{
error_list_append(&cli_errors, _("-D/--data-dir required when executing STANDBY RESTORE_CONFIG"));
}
config_file_required = false;
break;
case WITNESS_CREATE:
/* allow all parameters to be supplied */
break;
@@ -4660,3 +4974,42 @@ format_db_cli_params(const char *conninfo, char *output)
termPQExpBuffer(&buf);
}
bool copy_file(const char *old_filename, const char *new_filename)
{
FILE *ptr_old, *ptr_new;
int a;
ptr_old = fopen(old_filename, "r");
ptr_new = fopen(new_filename, "w");
if (ptr_old == NULL)
return false;
if (ptr_new == NULL)
{
fclose(ptr_old);
return false;
}
chmod(new_filename, S_IRUSR | S_IWUSR);
while(1)
{
a = fgetc(ptr_old);
if (!feof(ptr_old))
{
fputc(a, ptr_new);
}
else
{
break;
}
}
fclose(ptr_new);
fclose(ptr_old);
return true;
}

4
repmgr.h
View File

@@ -83,6 +83,8 @@ typedef struct
/* parameter used by STANDBY SWITCHOVER */
char remote_config_file[MAXLEN];
/* parameter used by STANDBY {ARCHIVE_CONFIG | RESTORE_CONFIG} */
char config_archive_dir[MAXLEN];
/* parameter used by CLUSTER CLEANUP */
int keep_history;
@@ -94,7 +96,7 @@ typedef struct
char localport[MAXLEN];
} t_runtime_options;
#define T_RUNTIME_OPTIONS_INITIALIZER { "", "", "", "", "", "", "", DEFAULT_WAL_KEEP_SEGMENTS, false, false, false, false, false, false, false, false, false, "smart", "", "", "", 0, "", "", "" }
#define T_RUNTIME_OPTIONS_INITIALIZER { "", "", "", "", "", "", "", DEFAULT_WAL_KEEP_SEGMENTS, false, false, false, false, false, false, false, false, false, "smart", "", "", "", "", 0, "", "", "" }
extern char repmgr_schema[MAXLEN];
extern bool config_file_found;