安装postgresql
安装pgpool
rpm -ivh http://www.pgpool.net/yum/rpms/3.7/redhat/rhel-7-x86_64/pgpool-II-release-3.7-1.noarch.rpm
yum -y install pgpool-II-pg95
yum -y install pgpool-II-pg95-debuginfo
yum -y install pgpool-II-pg95-devel
yum -y install pgpool-II-pg95-extensions
开机启动
systemctl enable pgpool添加Pgpool-II运行用户
[root@im110 pgpool-II]# useradd pgpool [root@im110 pgpool-II]# passwd pgpool Changing password for user pgpool. New password: Retype new password: passwd: all authentication tokens updated successfully. [root@im110 pgpool-II]# chown -R pgpool.pgpool /etc/pgpool-II [root@im110 pgpool-II]# mkdir -p /var/run/pgpool/ [root@im110 pgpool-II]# chown pgpool.pgpool /var/run/pgpool/
修改配置文件
先备份所有配置文件
vi pgpool.conf修改后如下
# ---------------------------- # pgPool-II configuration file # ---------------------------- # # This file consists of lines of the form: # # name = value # # Whitespace may be used. Comments are introduced with "#" anywhere on a line. # The complete list of parameter names and allowed values can be found in the # pgPool-II documentation. # # This file is read on server startup and when the server receives a SIGHUP # signal. If you edit the file on a running system, you have to SIGHUP the # server for the changes to take effect, or use "pgpool reload". Some # parameters, which are marked below, require a server shutdown and restart to # take effect. # #------------------------------------------------------------------------------ # CONNECTIONS #------------------------------------------------------------------------------ # - pgpool Connection Settings - listen_addresses = '*' # Host name or IP address to listen on: # '*' for all, '' for no TCP/IP connections # (change requires restart) port = 9999 # Port number # (change requires restart) socket_dir = '/var/run/postgresql' # Unix domain socket path # The Debian package defaults to # /var/run/postgresql # (change requires restart) listen_backlog_multiplier = 2 # Set the backlog parameter of listen(2) to # num_init_children * listen_backlog_multiplier. # (change requires restart) serialize_accept = off # whether to serialize accept() call to avoid thundering herd problem # (change requires restart) # - pgpool Communication Manager Connection Settings - pcp_listen_addresses = '*' # Host name or IP address for pcp process to listen on: # '*' for all, '' for no TCP/IP connections # (change requires restart) pcp_port = 9898 # Port number for pcp # (change requires restart) pcp_socket_dir = '/var/run/postgresql' # Unix domain socket path for pcp # The Debian package defaults to # /var/run/postgresql # (change requires restart) # - Backend Connection Settings - backend_hostname0 = '119.29.218.235' # Host name or IP address to connect to for backend 0 backend_port0 = 5432 # Port number for backend 0 backend_weight0 = 1 # Weight for backend 0 (only in load balancing mode) backend_data_directory0 = '/var/lib/pgsql/data' # Data directory for backend 0 backend_flag0 = 'ALLOW_TO_FAILOVER' # Controls various backend behavior # ALLOW_TO_FAILOVER, DISALLOW_TO_FAILOVER # or ALWAYS_MASTER backend_hostname1 = '111.231.195.197' backend_port1 = 5432 backend_weight1 = 1 backend_data_directory1 = '/var/lib/pgsql/data' backend_flag1 = 'ALLOW_TO_FAILOVER' # - Authentication - enable_pool_hba = on # Use pool_hba.conf for client authentication pool_passwd = 'pool_passwd' # File name of pool_passwd for md5 authentication. # "" disables pool_passwd. # (change requires restart) authentication_timeout = 60 # Delay in seconds to complete client authentication # 0 means no timeout. # - SSL Connections - ssl = off # Enable SSL support # (change requires restart) #ssl_key = './server.key' # Path to the SSL private key file # (change requires restart) #ssl_cert = './server.cert' # Path to the SSL public certificate file # (change requires restart) #ssl_ca_cert = '' # Path to a single PEM format file # containing CA root certificate(s) # (change requires restart) #ssl_ca_cert_dir = '' # Directory containing CA root certificate(s) # (change requires restart) #------------------------------------------------------------------------------ # POOLS #------------------------------------------------------------------------------ # - Concurrent session and pool size - num_init_children = 32 # Number of concurrent sessions allowed # (change requires restart) max_pool = 4 # Number of connection pool caches per connection # (change requires restart) # - Life time - child_life_time = 300 # Pool exits after being idle for this many seconds child_max_connections = 0 # Pool exits after receiving that many connections # 0 means no exit connection_life_time = 0 # Connection to backend closes after being idle for this many seconds # 0 means no close client_idle_limit = 0 # Client is disconnected after being idle for that many seconds # (even inside an explicit transactions!) # 0 means no disconnection #------------------------------------------------------------------------------ # LOGS #------------------------------------------------------------------------------ # - Where to log - log_destination = 'stderr' # Where to log # Valid values are combinations of stderr, # and syslog. Default to stderr. # - What to log - log_line_prefix = '%t: pid %p: ' # printf-style string to output at beginning of each log line. log_connections = off # Log connections log_hostname = off # Hostname will be shown in ps status # and in logs if connections are logged log_statement = off # Log all statements log_per_node_statement = off # Log all statements # with node and backend informations log_standby_delay = 'none' # Log standby delay # Valid values are combinations of always, # if_over_threshold, none # - Syslog specific - syslog_facility = 'LOCAL0' # Syslog local facility. Default to LOCAL0 syslog_ident = 'pgpool' # Syslog program identification string # Default to 'pgpool' # - Debug - #log_error_verbosity = default # terse, default, or verbose messages #client_min_messages = notice # values in order of decreasing detail: # debug5 # debug4 # debug3 # debug2 # debug1 # log # notice # warning # error #log_min_messages = warning # values in order of decreasing detail: # debug5 # debug4 # debug3 # debug2 # debug1 # info # notice # warning # error # log # fatal # panic #------------------------------------------------------------------------------ # FILE LOCATIONS #------------------------------------------------------------------------------ pid_file_name = '/var/run/pgpool/pgpool.pid' # PID file name # Can be specified as relative to the" # location of pgpool.conf file or # as an absolute path # (change requires restart) logdir = '/var/log/pgpool' # Directory of pgPool status file # (change requires restart) #------------------------------------------------------------------------------ # CONNECTION POOLING #------------------------------------------------------------------------------ connection_cache = on # Activate connection pools # (change requires restart) # Semicolon separated list of queries # to be issued at the end of a session # The default is for 8.3 and later reset_query_list = 'ABORT; DISCARD ALL' # The following one is for 8.2 and before #reset_query_list = 'ABORT; RESET ALL; SET SESSION AUTHORIZATION DEFAULT' #------------------------------------------------------------------------------ # REPLICATION MODE #------------------------------------------------------------------------------ replication_mode = off # Activate replication mode # (change requires restart) replicate_select = off # Replicate SELECT statements # when in replication mode # replicate_select is higher priority than # load_balance_mode. insert_lock = on # Automatically locks a dummy row or a table # with INSERT statements to keep SERIAL data # consistency # Without SERIAL, no lock will be issued lobj_lock_table = '' # When rewriting lo_creat command in # replication mode, specify table name to # lock # - Degenerate handling - replication_stop_on_mismatch = off # On disagreement with the packet kind # sent from backend, degenerate the node # which is most likely "minority" # If off, just force to exit this session failover_if_affected_tuples_mismatch = off # On disagreement with the number of affected # tuples in UPDATE/DELETE queries, then # degenerate the node which is most likely # "minority". # If off, just abort the transaction to # keep the consistency #------------------------------------------------------------------------------ # LOAD BALANCING MODE #------------------------------------------------------------------------------ load_balance_mode = off # Activate load balancing mode # (change requires restart) ignore_leading_white_space = on # Ignore leading white spaces of each query white_function_list = '' # Comma separated list of function names # that don't write to database # Regexp are accepted black_function_list = 'nextval,setval,nextval,setval' # Comma separated list of function names # that write to database # Regexp are accepted database_redirect_preference_list = '' # comma separated list of pairs of database and node id. # example: postgres:primary,mydb[0-4]:1,mydb[5-9]:2' # valid for streaming replicaton mode only. app_name_redirect_preference_list = '' # comma separated list of pairs of app name and node id. # example: 'psql:primary,myapp[0-4]:1,myapp[5-9]:standby' # valid for streaming replicaton mode only. allow_sql_comments = off # if on, ignore SQL comments when judging if load balance or # query cache is possible. # If off, SQL comments effectively prevent the judgment # (pre 3.4 behavior). #------------------------------------------------------------------------------ # MASTER/SLAVE MODE #------------------------------------------------------------------------------ master_slave_mode = off # Activate master/slave mode # (change requires restart) master_slave_sub_mode = 'stream' # Master/slave sub mode # Valid values are combinations stream, slony # or logical. Default is stream. # (change requires restart) # - Streaming - sr_check_period = 0 # Streaming replication check period # Disabled (0) by default sr_check_user = 'postgres' # Streaming replication check user # This is necessary even if you disable # streaming replication delay check with # sr_check_period = 0 sr_check_password = 'your pass word' # Password for streaming replication check user sr_check_database = 'postgres' # Database name for streaming replication check delay_threshold = 0 # Threshold before not dispatching query to standby node # Unit is in bytes # Disabled (0) by default # - Special commands - follow_master_command = '' # Executes this command after master failover # Special values: # %d = node id # %h = host name # %p = port number # %D = database cluster path # %m = new master node id # %H = hostname of the new master node # %M = old master node id # %P = old primary node id # %r = new master port number # %R = new master database cluster path # %% = '%' character #------------------------------------------------------------------------------ # HEALTH CHECK GLOBAL PARAMETERS #------------------------------------------------------------------------------ health_check_period = 0 # Health check period # Disabled (0) by default health_check_timeout = 20 # Health check timeout # 0 means no timeout health_check_user = 'nobody' # Health check user health_check_password = '' # Password for health check user health_check_database = '' # Database name for health check. If '', tries 'postgres' frist, then 'template1' health_check_max_retries = 0 # Maximum number of times to retry a failed health check before giving up. health_check_retry_delay = 1 # Amount of time to wait (in seconds) between retries. connect_timeout = 10000 # Timeout value in milliseconds before giving up to connect to backend. # Default is 10000 ms (10 second). Flaky network user may want to increase # the value. 0 means no timeout. # Note that this value is not only used for health check, # but also for ordinary conection to backend. #------------------------------------------------------------------------------ # HEALTH CHECK PER NODE PARAMETERS (OPTIONAL) #------------------------------------------------------------------------------ #health_check_period0 = 0 #health_check_timeout0 = 20 #health_check_user0 = 'nobody' #health_check_password0 = '' #health_check_database0 = '' #health_check_max_retries0 = 0 #health_check_retry_delay0 = 1 #connect_timeout0 = 10000 #------------------------------------------------------------------------------ # FAILOVER AND FAILBACK #------------------------------------------------------------------------------ failover_command = '/usr/local/bin/failover_stream.sh %d %H /tmp/trigger_file0' # Executes this command at failover # Special values: # %d = node id # %h = host name # %p = port number # %D = database cluster path # %m = new master node id # %H = hostname of the new master node # %M = old master node id # %P = old primary node id # %r = new master port number # %R = new master database cluster path # %% = '%' character failback_command = '' # Executes this command at failback. # Special values: # %d = node id # %h = host name # %p = port number # %D = database cluster path # %m = new master node id # %H = hostname of the new master node # %M = old master node id # %P = old primary node id # %r = new master port number # %R = new master database cluster path # %% = '%' character fail_over_on_backend_error = on # Initiates failover when reading/writing to the # backend communication socket fails # If set to off, pgpool will report an # error and disconnect the session. search_primary_node_timeout = 300 # Timeout in seconds to search for the # primary node when a failover occurs. # 0 means no timeout, keep searching # for a primary node forever. #------------------------------------------------------------------------------ # ONLINE RECOVERY #------------------------------------------------------------------------------ recovery_user = 'nobody' # Online recovery user recovery_password = '' # Online recovery password recovery_1st_stage_command = '' # Executes a command in first stage recovery_2nd_stage_command = '' # Executes a command in second stage recovery_timeout = 90 # Timeout in seconds to wait for the # recovering node's postmaster to start up # 0 means no wait client_idle_limit_in_recovery = 0 # Client is disconnected after being idle # for that many seconds in the second stage # of online recovery # 0 means no disconnection # -1 means immediate disconnection #------------------------------------------------------------------------------ # WATCHDOG #------------------------------------------------------------------------------ # - Enabling - use_watchdog = off # Activates watchdog # (change requires restart) # -Connection to up stream servers - trusted_servers = '' # trusted server list which are used # to confirm network connection # (hostA,hostB,hostC,...) # (change requires restart) ping_path = '/bin' # ping command path # (change requires restart) # - Watchdog communication Settings - wd_hostname = '' # Host name or IP address of this watchdog # (change requires restart) wd_port = 9000 # port number for watchdog service # (change requires restart) wd_priority = 1 # priority of this watchdog in leader election # (change requires restart) wd_authkey = '' # Authentication key for watchdog communication # (change requires restart) wd_ipc_socket_dir = '/var/run/postgresql' # Unix domain socket path for watchdog IPC socket # The Debian package defaults to # /var/run/postgresql # (change requires restart) # - Virtual IP control Setting - delegate_IP = '' # delegate IP address # If this is empty, virtual IP never bring up. # (change requires restart) if_cmd_path = '/sbin' # path to the directory where if_up/down_cmd exists # (change requires restart) if_up_cmd = 'ip addr add $_IP_$/24 dev eth0 label eth0:0' # startup delegate IP command # (change requires restart) if_down_cmd = 'ip addr del $_IP_$/24 dev eth0' # shutdown delegate IP command # (change requires restart) arping_path = '/usr/sbin' # arping command path # (change requires restart) arping_cmd = 'arping -U $_IP_$ -w 1' # arping command # (change requires restart) # - Behaivor on escalation Setting - clear_memqcache_on_escalation = on # Clear all the query cache on shared memory # when standby pgpool escalate to active pgpool # (= virtual IP holder). # This should be off if client connects to pgpool # not using virtual IP. # (change requires restart) wd_escalation_command = '' # Executes this command at escalation on new active pgpool. # (change requires restart) wd_de_escalation_command = '' # Executes this command when master pgpool resigns from being master. # (change requires restart) # - Watchdog consensus settings for failover - failover_when_quorum_exists = on # Only perform backend node failover # when the watchdog cluster holds the quorum # (change requires restart) failover_require_consensus = on # Perform failover when majority of Pgpool-II nodes # aggrees on the backend node status change # (change requires restart) allow_multiple_failover_requests_from_node = off # A Pgpool-II node can cast multiple votes # for building the consensus on failover # (change requires restart) # - Lifecheck Setting - # -- common -- wd_monitoring_interfaces_list = '' # Comma separated list of interfaces names to monitor. # if any interface from the list is active the watchdog will # consider the network is fine # 'any' to enable monitoring on all interfaces except loopback # '' to disable monitoring # (change requires restart) wd_lifecheck_method = 'heartbeat' # Method of watchdog lifecheck ('heartbeat' or 'query' or 'external') # (change requires restart) wd_interval = 10 # lifecheck interval (sec) > 0 # (change requires restart) # -- heartbeat mode -- wd_heartbeat_port = 9694 # Port number for receiving heartbeat signal # (change requires restart) wd_heartbeat_keepalive = 2 # Interval time of sending heartbeat signal (sec) # (change requires restart) wd_heartbeat_deadtime = 30 # Deadtime interval for heartbeat signal (sec) # (change requires restart) heartbeat_destination0 = 'host0_ip1' # Host name or IP address of destination 0 # for sending heartbeat signal. # (change requires restart) heartbeat_destination_port0 = 9694 # Port number of destination 0 for sending # heartbeat signal. Usually this is the # same as wd_heartbeat_port. # (change requires restart) heartbeat_device0 = '' # Name of NIC device (such like 'eth0') # used for sending/receiving heartbeat # signal to/from destination 0. # This works only when this is not empty # and pgpool has root privilege. # (change requires restart) #heartbeat_destination1 = 'host0_ip2' #heartbeat_destination_port1 = 9694 #heartbeat_device1 = '' # -- query mode -- wd_life_point = 3 # lifecheck retry times # (change requires restart) wd_lifecheck_query = 'SELECT 1' # lifecheck query to pgpool from watchdog # (change requires restart) wd_lifecheck_dbname = 'template1' # Database name connected for lifecheck # (change requires restart) wd_lifecheck_user = 'nobody' # watchdog user monitoring pgpools in lifecheck # (change requires restart) wd_lifecheck_password = '' # Password for watchdog user in lifecheck # (change requires restart) # - Other pgpool Connection Settings - #other_pgpool_hostname0 = 'host0' # Host name or IP address to connect to for other pgpool 0 # (change requires restart) #other_pgpool_port0 = 5432 # Port number for other pgpool 0 # (change requires restart) #other_wd_port0 = 9000 # Port number for other watchdog 0 # (change requires restart) #other_pgpool_hostname1 = 'host1' #other_pgpool_port1 = 5432 #other_wd_port1 = 9000 #------------------------------------------------------------------------------ # OTHERS #------------------------------------------------------------------------------ relcache_expire = 0 # Life time of relation cache in seconds. # 0 means no cache expiration(the default). # The relation cache is used for cache the # query result against PostgreSQL system # catalog to obtain various information # including table structures or if it's a # temporary table or not. The cache is # maintained in a pgpool child local memory # and being kept as long as it survives. # If someone modify the table by using # ALTER TABLE or some such, the relcache is # not consistent anymore. # For this purpose, cache_expiration # controls the life time of the cache. relcache_size = 256 # Number of relation cache # entry. If you see frequently: # "pool_search_relcache: cache replacement happend" # in the pgpool log, you might want to increate this number. check_temp_table = on # If on, enable temporary table check in SELECT statements. # This initiates queries against system catalog of primary/master # thus increases load of master. # If you are absolutely sure that your system never uses temporary tables # and you want to save access to primary/master, you could turn this off. # Default is on. check_unlogged_table = on # If on, enable unlogged table check in SELECT statements. # This initiates queries against system catalog of primary/master # thus increases load of master. # If you are absolutely sure that your system never uses unlogged tables # and you want to save access to primary/master, you could turn this off. # Default is on. #------------------------------------------------------------------------------ # IN MEMORY QUERY MEMORY CACHE #------------------------------------------------------------------------------ memory_cache_enabled = off # If on, use the memory cache functionality, off by default memqcache_method = 'shmem' # Cache storage method. either 'shmem'(shared memory) or # 'memcached'. 'shmem' by default # (change requires restart) memqcache_memcached_host = 'localhost' # Memcached host name or IP address. Mandatory if # memqcache_method = 'memcached'. # Defaults to localhost. # (change requires restart) memqcache_memcached_port = 11211 # Memcached port number. Mondatory if memqcache_method = 'memcached'. # Defaults to 11211. # (change requires restart) memqcache_total_size = 67108864 # Total memory size in bytes for storing memory cache. # Mandatory if memqcache_method = 'shmem'. # Defaults to 64MB. # (change requires restart) memqcache_max_num_cache = 1000000 # Total number of cache entries. Mandatory # if memqcache_method = 'shmem'. # Each cache entry consumes 48 bytes on shared memory. # Defaults to 1,000,000(45.8MB). # (change requires restart) memqcache_expire = 0 # Memory cache entry life time specified in seconds. # 0 means infinite life time. 0 by default. # (change requires restart) memqcache_auto_cache_invalidation = on # If on, invalidation of query cache is triggered by corresponding # DDL/DML/DCL(and memqcache_expire). If off, it is only triggered # by memqcache_expire. on by default. # (change requires restart) memqcache_maxcache = 409600 # Maximum SELECT result size in bytes. # Must be smaller than memqcache_cache_block_size. Defaults to 400KB. # (change requires restart) memqcache_cache_block_size = 1048576 # Cache block size in bytes. Mandatory if memqcache_method = 'shmem'. # Defaults to 1MB. # (change requires restart) memqcache_oiddir = '/var/log/pgpool/oiddir' # Temporary work directory to record table oids # (change requires restart) white_memqcache_table_list = '' # Comma separated list of table names to memcache # that don't write to database # Regexp are accepted black_memqcache_table_list = '' # Comma separated list of table names not to memcache # that don't write to database # Regexp are accepted
vi pool_hba.conf修改后如下
# pgpool Client Authentication Configuration File # =============================================== # # The format rule in this file follows the rules in the PostgreSQL # Administrator's Guide. Refer to chapter "Client Authentication" for a # complete description. A short synopsis follows. # # This file controls: which hosts are allowed to connect, how clients # are authenticated, which user names they can use, which databases they # can access. Records take one of these forms: # # local DATABASE USER METHOD [OPTION] # host DATABASE USER CIDR-ADDRESS METHOD [OPTION] # # (The uppercase items must be replaced by actual values.) # # The first field is the connection type: "local" is a Unix-domain # socket, "host" is either a plain or SSL-encrypted TCP/IP socket. # # DATABASE can be "all", "sameuser", a database name, or a comma-separated # list thereof. Note that "samegroup" like in PostgreSQL's pg_hba.conf # file is not supported, since pgpool does not know which group a user # belongs to. Also note that the database specified here may not exist in # the backend PostgreSQL. pgpool will authenticate based on the database's # name, not based on whether it exists or not. # # USER can be "all", a user name, or a comma-separated list thereof. In # both the DATABASE and USER fields you can also write a file name prefixed # with "@" to include names from a separate file. Note that a group name # prefixed with "+" like in PostgreSQL's pg_hba.conf file is not supported # because of the same reason as "samegroup" token. Also note that a user # name specified here may not exist in the backend PostgreSQL. pgpool will # authenticate based on the user's name, not based on whether he/she exists. # # CIDR-ADDRESS specifies the set of hosts the record matches. # It is made up of an IP address and a CIDR mask that is an integer # (between 0 and 32 (IPv4) that specifies the number of significant bits in # the mask. Alternatively, you can write an IP address and netmask in # separate columns to specify the set of hosts. # # METHOD can be "trust", "reject", "md5" or "pam". Note that "pam" sends passwords # in clear text. # # OPTION is the name of the PAM service. Default service name is "pgpool" # # Database and user names containing spaces, commas, quotes and other special # characters must be quoted. Quoting one of the keywords "all" or "sameuser" # makes the name lose its special character, and just match a database or # username with that name. # # This file is read on pgpool startup. If you edit the file on a running # system, you have to restart the pgpool for the changes to take effect. # Put your actual configuration here # ---------------------------------- # # If you want to allow non-local connections, you need to add more # "host" records. In that case you will also need to make pgpool listen # on a non-local interface via the listen_addresses configuration parameter. # # TYPE DATABASE USER CIDR-ADDRESS METHOD # "local" is for Unix domain socket connections only local all all trust # IPv4 local connections: host all all 0.0.0.0/0 md5 #host all all 127.0.0.1/32 trust host all all ::1/128 trust
启用配置文件pool_passwd
[root@pgpool etc]# pg_md5 -m -p -u postgres pool_passwd
password:
创建主从切换脚本
[root@pgpool bin]# vi /usr/local/bin/failover_stream.sh # Failover command for streaming replication. # This script assumes that DB node 0 is primary, and 1 is standby. # # If standby goes down, do nothing. If primary goes down, create a # trigger file so that standby takes over primary node. # # Arguments: $1: failed node id. $2: new master hostname. $3: path to # trigger file. failed_node=$1 new_master=$2 trigger_file=$3 # Do nothing if standby goes down. if [ $failed_node = 1 ]; then exit 0; fi # Create the trigger file. /usr/bin/ssh -T $new_master /bin/touch $trigger_file exit 0; [root@pgpool bin]# chmod 700 failover_stream.sh
启动pgpool
[root@VM_176_134_centos pgpool-II]# pgpool -n -d > /tmp/pgpool.log 2>&1 & [1] 5894 [root@VM_176_134_centos pgpool-II]# ps -aux|grep pgpool root 763 0.0 0.0 187508 2348 pts/0 S 14:29 0:00 su pgpool pgpool 764 0.0 0.0 116036 2712 pts/0 S 14:29 0:00 bash root 2292 0.0 0.0 126244 1756 pts/2 S+ 14:53 0:00 vi /var/log/pgpool/pgpool_status root 5894 0.0 0.1 90812 6656 pts/0 S 15:52 0:00 pgpool -n -d root 5895 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5896 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5897 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5898 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5899 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5900 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5901 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5902 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5903 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5904 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5905 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5906 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5907 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5908 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5909 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5910 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5911 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5912 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5913 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5914 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5915 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5916 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5917 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5918 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5919 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5920 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5921 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5922 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5923 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5924 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5925 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5926 0.0 0.0 90812 1964 pts/0 S 15:52 0:00 pgpool: wait for connection request root 5927 0.0 0.0 90816 1724 pts/0 S 15:52 0:00 pgpool: PCP: wait for connection request root 5928 0.0 0.0 90812 1728 pts/0 S 15:52 0:00 pgpool: worker process root 5929 0.0 0.0 90812 1728 pts/0 S 15:52 0:00 pgpool: health check process(0) root 5960 0.0 0.0 112644 960 pts/0 R+ 15:53 0:00 grep --color=auto pgpool [root@VM_176_134_centos pgpool-II]#
启动两台服务器数据库
[root@VM_176_134_centos pgpool-II]# systemctl start postgresql [root@VM_176_134_centos pgpool-II]# ps -aux|grep postgresql root 6100 0.0 0.0 112644 968 pts/0 S+ 15:55 0:00 grep --color=auto postgresql [root@VM_176_134_centos pgpool-II]# ps -aux|grep postgres postgres 6086 0.0 0.2 232344 9368 ? S 15:55 0:00 /usr/bin/postgres -D /var/lib/pgsql/data -p 5432 postgres 6087 0.0 0.0 189968 1492 ? Ss 15:55 0:00 postgres: logger process postgres 6089 0.0 0.0 232344 1716 ? Ss 15:55 0:00 postgres: checkpointer process postgres 6090 0.0 0.0 232344 1724 ? Ss 15:55 0:00 postgres: writer process postgres 6091 0.0 0.0 232344 1484 ? Ss 15:55 0:00 postgres: wal writer process postgres 6092 0.0 0.0 233168 2872 ? Ss 15:55 0:00 postgres: autovacuum launcher process postgres 6093 0.0 0.0 192220 1688 ? Ss 15:55 0:00 postgres: stats collector process root 6103 0.0 0.0 112644 964 pts/0 S+ 15:55 0:00 grep --color=auto postgres [root@VM_176_134_centos pgpool-II]#
连接测试
1.连接pgpool，能看到235的数据
2.在pgpool新建test_pgpool表，235的数据库也可以看到表，但备机197上似乎没有看到test_pgpool
3.修改配置文件
vi pgpool.conf 改下面两个属性 replication_mode = true load_balance_mode = true 然后关闭客户端的连接 235上停止pgpool: pgpool stop 235上启动pgpool: pgpool
4.通过主节点建表test_pgpool2，可以看到主、备节点均有test_pgpool2
5.关掉235上的postgresql,看看能否切换到197
[root@VM_176_134_centos pgpool-II]# systemctl stop postgresql [root@VM_176_134_centos pgpool-II]# ps -aux|grep postgres root 7361 0.0 0.0 90912 3060 ? S 16:16 0:00 pgpool: postgres postgres 113.116.51.86(62810) idle root 8189 0.0 0.0 112644 964 pts/0 R+ 16:31 0:00 grep --color=auto postgres [root@VM_176_134_centos pgpool-II]#
可以看到已经切换到197了，表明在运行中，如果235挂掉了，还有197可用。
但是发现再启动235后的数据库后，pgpool不会自动切回来，可能切换脚本有问题，这个不弄了，等专业的来
参考
官方文档：pgpool-II 入门教程