YAML Configuration Settings

Dynamic configuration settings

Dynamic configuration is stored in the DCS (Distributed Configuration Store) and applied on all cluster nodes. Some parameters, like loop_wait, ttl, postgresql.parameters.max_connections, postgresql.parameters.max_worker_processes and so on could be set only in the dynamic configuration. Some other parameters like postgresql.listen, postgresql.data_dir could be set only locally, i.e. in the Patroni config file or via configuration variable. In most cases the local configuration will override the dynamic configuration. In order to change the dynamic configuration you can use either patronictl edit-config tool or Patroni REST API.

  • loop_wait: the number of seconds the loop will sleep. Default value: 10
  • ttl: the TTL to acquire the leader lock (in seconds). Think of it as the length of time before initiation of the automatic failover process. Default value: 30
  • retry_timeout: timeout for DCS and PostgreSQL operation retries (in seconds). DCS or network issues shorter than this will not cause Patroni to demote the leader. Default value: 10
  • maximum_lag_on_failover: the maximum bytes a follower may lag to be able to participate in leader election.
  • maximum_lag_on_syncnode: the maximum bytes a synchronous follower may lag before it is considered as an unhealthy candidate and swapped by healthy asynchronous follower. Patroni utilize the max replica lsn if there is more than one follower, otherwise it will use leader’s current wal lsn. Default is -1, Patroni will not take action to swap synchronous unhealthy follower when the value is set to 0 or below. Please set the value high enough so Patroni won’t swap synchrounous follower fequently during high transaction volume.
  • max_timelines_history: maximum number of timeline history items kept in DCS. Default value: 0. When set to 0, it keeps the full history in DCS.
  • master_start_timeout: the amount of time a master is allowed to recover from failures before failover is triggered (in seconds). Default is 300 seconds. When set to 0 failover is done immediately after a crash is detected if possible. When using asynchronous replication a failover can cause lost transactions. Worst case failover time for master failure is: loop_wait + master_start_timeout + loop_wait, unless master_start_timeout is zero, in which case it’s just loop_wait. Set the value according to your durability/availability tradeoff.
  • master_stop_timeout: The number of seconds Patroni is allowed to wait when stopping Postgres and effective only when synchronous_mode is enabled. When set to > 0 and the synchronous_mode is enabled, Patroni sends SIGKILL to the postmaster if the stop operation is running for more than the value set by master_stop_timeout. Set the value according to your durability/availability tradeoff. If the parameter is not set or set <= 0, master_stop_timeout does not apply.
  • synchronous_mode: turns on synchronous replication mode. In this mode a replica will be chosen as synchronous and only the latest leader and synchronous replica are able to participate in leader election. Synchronous mode makes sure that successfully committed transactions will not be lost at failover, at the cost of losing availability for writes when Patroni cannot ensure transaction durability. See replication modes documentation for details.
  • synchronous_mode_strict: prevents disabling synchronous replication if no synchronous replicas are available, blocking all client writes to the master. See replication modes documentation for details.
  • postgresql:
    • use_pg_rewind: whether or not to use pg_rewind. Defaults to false.
    • use_slots: whether or not to use replication slots. Defaults to true on PostgreSQL 9.4+.
    • recovery_conf: additional configuration settings written to recovery.conf when configuring follower. There is no recovery.conf anymore in PostgreSQL 12, but you may continue using this section, because Patroni handles it transparently.
    • parameters: list of configuration settings for Postgres.
  • standby_cluster: if this section is defined, we want to bootstrap a standby cluster.
    • host: an address of remote master
    • port: a port of remote master
    • primary_slot_name: which slot on the remote master to use for replication. This parameter is optional, the default value is derived from the instance name (see function slot_name_from_member_name).
    • create_replica_methods: an ordered list of methods that can be used to bootstrap standby leader from the remote master, can be different from the list defined in PostgreSQL
    • restore_command: command to restore WAL records from the remote master to standby leader, can be different from the list defined in PostgreSQL
    • archive_cleanup_command: cleanup command for standby leader
    • recovery_min_apply_delay: how long to wait before actually apply WAL records on a standby leader
  • slots: define permanent replication slots. These slots will be preserved during switchover/failover. The logical slots are copied from the primary to a standby with restart, and after that their position advanced every loop_wait seconds (if necessary). Copying logical slot files performed via libpq connection and using either rewind or superuser credentials (see postgresql.authentication section). There is always a chance that the logical slot position on the replica is a bit behind the former primary, therefore application should be prepared that some messages could be received the second time after the failover. The easiest way of doing so - tracking confirmed_flush_lsn. Enabling permanent logical replication slots requires postgresql.use_slots to be set and will also automatically enable the hot_standby_feedback. Since the failover of logical replication slots is unsafe on PostgreSQL 9.6 and older and PostgreSQL version 10 is missing some important functions, the feature only works with PostgreSQL 11+.
    • my_slot_name: the name of replication slot. If the permanent slot name matches with the name of the current primary it will not be created. Everything else is the responsibility of the operator to make sure that there are no clashes in names between replication slots automatically created by Patroni for members and permanent replication slots.
      • type: slot type. Could be physical or logical. If the slot is logical, you have to additionally define database and plugin.
      • database: the database name where logical slots should be created.
      • plugin: the plugin name for the logical slot.
  • ignore_slots: list of sets of replication slot properties for which Patroni should ignore matching slots. This configuration/feature/etc. is useful when some replication slots are managed outside of Patroni. Any subset of matching properties will cause a slot to be ignored.
    • name: the name of the replication slot.
    • type: slot type. Can be physical or logical. If the slot is logical, you may additionally define database and/or plugin.
    • database: the database name (when matching a logical slot).
    • plugin: the logical decoding plugin (when matching a logical slot).

Note: slots is a hashmap while ignore_slots is an array. For example:

slots:
  permanent_logical_slot_name:
    type: logical
    database: my_db
    plugin: test_decoding
  permanent_physical_slot_name:
    type: physical
  ...
ignore_slots:
  - name: ignored_logical_slot_name
    type: logical
    database: my_db
    plugin: test_decoding
  - name: ignored_physical_slot_name
    type: physical
  ...

Global/Universal

  • name: the name of the host. Must be unique for the cluster.
  • namespace: path within the configuration store where Patroni will keep information about the cluster. Default value: “/service”
  • scope: cluster name

Log

  • level: sets the general logging level. Default value is INFO (see the docs for Python logging)
  • traceback_level: sets the level where tracebacks will be visible. Default value is ERROR. Set it to DEBUG if you want to see tracebacks only if you enable log.level=DEBUG.
  • format: sets the log formatting string. Default value is %(asctime)s %(levelname)s: %(message)s (see the LogRecord attributes)
  • dateformat: sets the datetime formatting string. (see the formatTime() documentation)
  • max_queue_size: Patroni is using two-step logging. Log records are written into the in-memory queue and there is a separate thread which pulls them from the queue and writes to stderr or file. The maximum size of the internal queue is limited by default by 1000 records, which is enough to keep logs for the past 1h20m.
  • dir: Directory to write application logs to. The directory must exist and be writable by the user executing Patroni. If you set this value, the application will retain 4 25MB logs by default. You can tune those retention values with file_num and file_size (see below).
  • file_num: The number of application logs to retain.
  • file_size: Size of patroni.log file (in bytes) that triggers a log rolling.
  • loggers: This section allows redefining logging level per python module
    • patroni.postmaster: WARNING
    • urllib3: DEBUG

Bootstrap configuration

  • bootstrap:
    • dcs: This section will be written into /<namespace>/<scope>/config of the given configuration store after initializing of new cluster. The global dynamic configuration for the cluster. Under the bootstrap.dcs you can put any of the parameters described in the Dynamic Configuration settings and after Patroni initialized (bootstrapped) the new cluster, it will write this section into /<namespace>/<scope>/config of the configuration store. All later changes of bootstrap.dcs will not take any effect! If you want to change them please use either patronictl edit-config or Patroni REST API.
    • method: custom script to use for bootstrapping this cluster. See custom bootstrap methods documentation for details. When initdb is specified revert to the default initdb command. initdb is also triggered when no method parameter is present in the configuration file.
    • initdb: List options to be passed on to initdb.
      • - data-checksums: Must be enabled when pg_rewind is needed on 9.3.
      • - encoding: UTF8: default encoding for new databases.
      • - locale: UTF8: default locale for new databases.
    • pg_hba: list of lines that you should add to pg_hba.conf.
      • - host all all 0.0.0.0/0 md5.
      • - host replication replicator 127.0.0.1/32 md5: A line like this is required for replication.
    • users: Some additional users which need to be created after initializing new cluster
      • admin: the name of user
        • password: zalando:
        • options: list of options for CREATE USER statement
          • - createrole
          • - createdb
    • post_bootstrap or post_init: An additional script that will be executed after initializing the cluster. The script receives a connection string URL (with the cluster superuser as a user name). The PGPASSFILE variable is set to the location of pgpass file.

Consul

Most of the parameters are optional, but you have to specify one of the host or url

  • host: the host:port for the Consul local agent.
  • url: url for the Consul local agent, in format: http(s)://host:port.
  • port: (optional) Consul port.
  • scheme: (optional) http or https, defaults to http.
  • token: (optional) ACL token.
  • verify: (optional) whether to verify the SSL certificate for HTTPS requests.
  • cacert: (optional) The ca certificate. If present it will enable validation.
  • cert: (optional) file with the client certificate.
  • key: (optional) file with the client key. Can be empty if the key is part of cert.
  • dc: (optional) Datacenter to communicate with. By default the datacenter of the host is used.
  • consistency: (optional) Select consul consistency mode. Possible values are default, consistent, or stale (more details in consul API reference)
  • checks: (optional) list of Consul health checks used for the session. By default an empty list is used.
  • register_service: (optional) whether or not to register a service with the name defined by the scope parameter and the tag master, replica or standby-leader depending on the node’s role. Defaults to false.
  • service_tags: (optional) additional static tags to add to the Consul service apart from the role (master/replica/standby-leader). By default an empty list is used.
  • service_check_interval: (optional) how often to perform health check against registered url.

The token needs to have the following ACL permissions:

service_prefix "${scope}" {
    policy = "write"
}
key_prefix "${namespace}/${scope}" {
    policy = "write"
}
session_prefix "" {
    policy = "write"
}

Etcd

Most of the parameters are optional, but you have to specify one of the host, hosts, url, proxy or srv

  • host: the host:port for the etcd endpoint.
  • hosts: list of etcd endpoint in format host1:port1,host2:port2,etc… Could be a comma separated string or an actual yaml list.
  • use_proxies: If this parameter is set to true, Patroni will consider hosts as a list of proxies and will not perform a topology discovery of etcd cluster.
  • url: url for the etcd.
  • proxy: proxy url for the etcd. If you are connecting to the etcd using proxy, use this parameter instead of url.
  • srv: Domain to search the SRV record(s) for cluster autodiscovery. Patroni will try to query these SRV service names for specified domain (in that order until first success): _etcd-client-ssl, _etcd-client, _etcd-ssl, _etcd, _etcd-server-ssl, _etcd-server. If SRV records for _etcd-server-ssl or _etcd-server are retrieved then ETCD peer protocol is used do query ETCD for available members. Otherwise hosts from SRV records will be used.
  • srv_suffix: Configures a suffix to the SRV name that is queried during discovery. Use this flag to differentiate between multiple etcd clusters under the same domain. Works only with conjunction with srv. For example, if srv_suffix: foo and srv: example.org are set, the following DNS SRV query is made:_etcd-client-ssl-foo._tcp.example.com (and so on for every possible ETCD SRV service name).
  • protocol: (optional) http or https, if not specified http is used. If the url or proxy is specified - will take protocol from them.
  • username: (optional) username for etcd authentication.
  • password: (optional) password for etcd authentication.
  • cacert: (optional) The ca certificate. If present it will enable validation.
  • cert: (optional) file with the client certificate.
  • key: (optional) file with the client key. Can be empty if the key is part of cert.

Etcdv3

If you want that Patroni works with Etcd cluster via protocol version 3, you need to use the etcd3 section in the Patroni configuration file. All configuration parameters are the same as for etcd.

Warning

Keys created with protocol version 2 are not visible with protocol version 3 and the other way around, therefore it is not possible to switch from etcd to etcd3 just by updating Patroni config file.

ZooKeeper

  • hosts: List of ZooKeeper cluster members in format: [‘host1:port1’, ‘host2:port2’, ‘etc…’].
  • use_ssl: (optional) Whether SSL is used or not. Defaults to false. If set to false, all SSL specific parameters are ignored.
  • cacert: (optional) The CA certificate. If present it will enable validation.
  • cert: (optional) File with the client certificate.
  • key: (optional) File with the client key.
  • key_password: (optional) The client key password.
  • verify: (optional) Whether to verify certificate or not. Defaults to true.

Note

It is required to install kazoo>=2.6.0 to support SSL.

Exhibitor

  • hosts: initial list of Exhibitor (ZooKeeper) nodes in format: ‘host1,host2,etc…’. This list updates automatically whenever the Exhibitor (ZooKeeper) cluster topology changes.
  • poll_interval: how often the list of ZooKeeper and Exhibitor nodes should be updated from Exhibitor.
  • port: Exhibitor port.

Kubernetes

  • bypass_api_service: (optional) When communicating with the Kubernetes API, Patroni is usually relying on the kubernetes service, the address of which is exposed in the pods via the KUBERNETES_SERVICE_HOST environment variable. If bypass_api_service is set to true, Patroni will resolve the list of API nodes behind the service and connect directly to them.
  • namespace: (optional) Kubernetes namespace where Patroni pod is running. Default value is default.
  • labels: Labels in format {label1: value1, label2: value2}. These labels will be used to find existing objects (Pods and either Endpoints or ConfigMaps) associated with the current cluster. Also Patroni will set them on every object (Endpoint or ConfigMap) it creates.
  • scope_label: (optional) name of the label containing cluster name. Default value is cluster-name.
  • role_label: (optional) name of the label containing role (master or replica). Patroni will set this label on the pod it runs in. Default value is role.
  • use_endpoints: (optional) if set to true, Patroni will use Endpoints instead of ConfigMaps to run leader elections and keep cluster state.
  • pod_ip: (optional) IP address of the pod Patroni is running in. This value is required when use_endpoints is enabled and is used to populate the leader endpoint subsets when the pod’s PostgreSQL is promoted.
  • ports: (optional) if the Service object has the name for the port, the same name must appear in the Endpoint object, otherwise service won’t work. For example, if your service is defined as {Kind: Service, spec: {ports: [{name: postgresql, port: 5432, targetPort: 5432}]}}, then you have to set kubernetes.ports: [{"name": "postgresql", "port": 5432}] and Patroni will use it for updating subsets of the leader Endpoint. This parameter is used only if kubernetes.use_endpoints is set.
  • cacert: (optional) Specifies the file with the CA_BUNDLE file with certificates of trusted CAs to use while verifying Kubernetes API SSL certs. If not provided, patroni will use the value provided by the ServiceAccount secret.

Raft

  • self_addr: ip:port to listen on for Raft connections. The self_addr must be accessible from other nodes of the cluster. If not set, the node will not participate in consensus.
  • bind_addr: (optional) ip:port to listen on for Raft connections. If not specified the self_addr will be used.
  • partner_addrs: list of other Patroni nodes in the cluster in format: [‘ip1:port’, ‘ip2:port’, ‘etc…’]
  • data_dir: directory where to store Raft log and snapshot. If not specified the current working directory is used.
  • password: (optional) Encrypt Raft traffic with a specified password, requires cryptography python module.

Short FAQ about Raft implementation

  • Q: How to list all the nodes providing consensus?

    A: syncobj_admin -conn host:port -status where the host:port is the address of one of the cluster nodes

  • Q: Node that was a part of consensus and has gone and I can’t reuse the same IP for other node. How to remove this node from the consensus?

    A: syncobj_admin -conn host:port -remove host2:port2 where the host2:port2 is the address of the node you want to remove from consensus.

  • Q: Where to get the syncobj_admin utility?

    A: It is installed together with pysyncobj module (python RAFT implementation), which is Patroni dependency.

  • Q: it is possible to run Patroni node without adding in to the consensus?

    A: Yes, just comment out or remove raft.self_addr from Patroni configuration.

  • Q: It is possible to run Patroni and PostgreSQL only on two nodes?

    A: Yes, on the third node you can run patroni_raft_controller (without Patroni and PostgreSQL). In such a setup, one can temporarily lose one node without affecting the primary.

PostgreSQL

  • postgresql:
    • authentication:
      • superuser:
        • username: name for the superuser, set during initialization (initdb) and later used by Patroni to connect to the postgres.
        • password: password for the superuser, set during initialization (initdb).
        • sslmode: (optional) maps to the sslmode connection parameter, which allows a client to specify the type of TLS negotiation mode with the server. For more information on how each mode works, please visit the PostgreSQL documentation. The default mode is prefer.
        • sslkey: (optional) maps to the sslkey connection parameter, which specifies the location of the secret key used with the client’s certificate.
        • sslpassword: (optional) maps to the sslpassword connection parameter, which specifies the password for the secret key specified in sslkey.
        • sslcert: (optional) maps to the sslcert connection parameter, which specifies the location of the client certificate.
        • sslrootcert: (optional) maps to the sslrootcert connection parameter, which specifies the location of a file containing one ore more certificate authorities (CA) certificates that the client will use to verify a server’s certificate.
        • sslcrl: (optional) maps to the sslcrl connection parameter, which specifies the location of a file containing a certificate revocation list. A client will reject connecting to any server that has a certificate present in this list.
        • gssencmode: (optional) maps to the gssencmode connection parameter, which determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server
        • channel_binding: (optional) maps to the channel_binding connection parameter, which controls the client’s use of channel binding.
      • replication:
        • username: replication username; the user will be created during initialization. Replicas will use this user to access master via streaming replication
        • password: replication password; the user will be created during initialization.
        • sslmode: (optional) maps to the sslmode connection parameter, which allows a client to specify the type of TLS negotiation mode with the server. For more information on how each mode works, please visit the PostgreSQL documentation. The default mode is prefer.
        • sslkey: (optional) maps to the sslkey connection parameter, which specifies the location of the secret key used with the client’s certificate.
        • sslpassword: (optional) maps to the sslpassword connection parameter, which specifies the password for the secret key specified in sslkey.
        • sslcert: (optional) maps to the sslcert connection parameter, which specifies the location of the client certificate.
        • sslrootcert: (optional) maps to the sslrootcert connection parameter, which specifies the location of a file containing one ore more certificate authorities (CA) certificates that the client will use to verify a server’s certificate.
        • sslcrl: (optional) maps to the sslcrl connection parameter, which specifies the location of a file containing a certificate revocation list. A client will reject connecting to any server that has a certificate present in this list.
        • gssencmode: (optional) maps to the gssencmode connection parameter, which determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server
        • channel_binding: (optional) maps to the channel_binding connection parameter, which controls the client’s use of channel binding.
      • rewind:
        • username: name for the user for pg_rewind; the user will be created during initialization of postgres 11+ and all necessary permissions will be granted.
        • password: password for the user for pg_rewind; the user will be created during initialization.
        • sslmode: (optional) maps to the sslmode connection parameter, which allows a client to specify the type of TLS negotiation mode with the server. For more information on how each mode works, please visit the PostgreSQL documentation. The default mode is prefer.
        • sslkey: (optional) maps to the sslkey connection parameter, which specifies the location of the secret key used with the client’s certificate.
        • sslpassword: (optional) maps to the sslpassword connection parameter, which specifies the password for the secret key specified in sslkey.
        • sslcert: (optional) maps to the sslcert connection parameter, which specifies the location of the client certificate.
        • sslrootcert: (optional) maps to the sslrootcert connection parameter, which specifies the location of a file containing one ore more certificate authorities (CA) certificates that the client will use to verify a server’s certificate.
        • sslcrl: (optional) maps to the sslcrl connection parameter, which specifies the location of a file containing a certificate revocation list. A client will reject connecting to any server that has a certificate present in this list.
        • gssencmode: (optional) maps to the gssencmode connection parameter, which determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server
        • channel_binding: (optional) maps to the channel_binding connection parameter, which controls the client’s use of channel binding.
    • callbacks: callback scripts to run on certain actions. Patroni will pass the action, role and cluster name. (See scripts/aws.py as an example of how to write them.)
      • on_reload: run this script when configuration reload is triggered.
      • on_restart: run this script when the postgres restarts (without changing role).
      • on_role_change: run this script when the postgres is being promoted or demoted.
      • on_start: run this script when the postgres starts.
      • on_stop: run this script when the postgres stops.
    • connect_address: IP address + port through which Postgres is accessible from other nodes and applications.
    • create_replica_methods: an ordered list of the create methods for turning a Patroni node into a new replica. “basebackup” is the default method; other methods are assumed to refer to scripts, each of which is configured as its own config item. See custom replica creation methods documentation for further explanation.
    • data_dir: The location of the Postgres data directory, either existing or to be initialized by Patroni.
    • config_dir: The location of the Postgres configuration directory, defaults to the data directory. Must be writable by Patroni.
    • bin_dir: Path to PostgreSQL binaries (pg_ctl, pg_rewind, pg_basebackup, postgres). The default value is an empty string meaning that PATH environment variable will be used to find the executables.
    • listen: IP address + port that Postgres listens to; must be accessible from other nodes in the cluster, if you’re using streaming replication. Multiple comma-separated addresses are permitted, as long as the port component is appended after to the last one with a colon, i.e. listen: 127.0.0.1,127.0.0.2:5432. Patroni will use the first address from this list to establish local connections to the PostgreSQL node.
    • use_unix_socket: specifies that Patroni should prefer to use unix sockets to connect to the cluster. Default value is false. If unix_socket_directories is defined, Patroni will use the first suitable value from it to connect to the cluster and fallback to tcp if nothing is suitable. If unix_socket_directories is not specified in postgresql.parameters, Patroni will assume that the default value should be used and omit host from the connection parameters.
    • use_unix_socket_repl: specifies that Patroni should prefer to use unix sockets for replication user cluster connection. Default value is false. If unix_socket_directories is defined, Patroni will use the first suitable value from it to connect to the cluster and fallback to tcp if nothing is suitable. If unix_socket_directories is not specified in postgresql.parameters, Patroni will assume that the default value should be used and omit host from the connection parameters.
    • pgpass: path to the .pgpass password file. Patroni creates this file before executing pg_basebackup, the post_init script and under some other circumstances. The location must be writable by Patroni.
    • recovery_conf: additional configuration settings written to recovery.conf when configuring follower.
    • custom_conf : path to an optional custom postgresql.conf file, that will be used in place of postgresql.base.conf. The file must exist on all cluster nodes, be readable by PostgreSQL and will be included from its location on the real postgresql.conf. Note that Patroni will not monitor this file for changes, nor backup it. However, its settings can still be overridden by Patroni’s own configuration facilities - see dynamic configuration for details.
    • parameters: list of configuration settings for Postgres. Many of these are required for replication to work.
    • pg_hba: list of lines that Patroni will use to generate pg_hba.conf. This parameter has higher priority than bootstrap.pg_hba. Together with dynamic configuration it simplifies management of pg_hba.conf.
      • - host all all 0.0.0.0/0 md5.
      • - host replication replicator 127.0.0.1/32 md5: A line like this is required for replication.
    • pg_ident: list of lines that Patroni will use to generate pg_ident.conf. Together with dynamic configuration it simplifies management of pg_ident.conf.
      • - mapname1 systemname1 pguser1.
      • - mapname1 systemname2 pguser2.
    • pg_ctl_timeout: How long should pg_ctl wait when doing start, stop or restart. Default value is 60 seconds.
    • use_pg_rewind: try to use pg_rewind on the former leader when it joins cluster as a replica.
    • remove_data_directory_on_rewind_failure: If this option is enabled, Patroni will remove the PostgreSQL data directory and recreate the replica. Otherwise it will try to follow the new leader. Default value is false.
    • remove_data_directory_on_diverged_timelines: Patroni will remove the PostgreSQL data directory and recreate the replica if it notices that timelines are diverging and the former master can not start streaming from the new master. This option is useful when pg_rewind can not be used. Default value is false.
    • replica_method: for each create_replica_methods other than basebackup, you would add a configuration section of the same name. At a minimum, this should include “command” with a full path to the actual script to be executed. Other configuration parameters will be passed along to the script in the form “parameter=value”.
    • pre_promote: a fencing script that executes during a failover after acquiring the leader lock but before promoting the replica. If the script exits with a non-zero code, Patroni does not promote the replica and removes the leader key from DCS.

REST API

  • restapi:
    • connect_address: IP address (or hostname) and port, to access the Patroni’s REST API. All the members of the cluster must be able to connect to this address, so unless the Patroni setup is intended for a demo inside the localhost, this address must be a non “localhost” or loopback address (ie: “localhost” or “127.0.0.1”). It can serve as an endpoint for HTTP health checks (read below about the “listen” REST API parameter), and also for user queries (either directly or via the REST API), as well as for the health checks done by the cluster members during leader elections (for example, to determine whether the master is still running, or if there is a node which has a WAL position that is ahead of the one doing the query; etc.) The connect_address is put in the member key in DCS, making it possible to translate the member name into the address to connect to its REST API.
    • listen: IP address (or hostname) and port that Patroni will listen to for the REST API - to provide also the same health checks and cluster messaging between the participating nodes, as described above. to provide health-check information for HAProxy (or any other load balancer capable of doing a HTTP “OPTION” or “GET” checks).
    • authentication: (optional)
      • username: Basic-auth username to protect unsafe REST API endpoints.
      • password: Basic-auth password to protect unsafe REST API endpoints.
    • certfile: (optional): Specifies the file with the certificate in the PEM format. If the certfile is not specified or is left empty, the API server will work without SSL.
    • keyfile: (optional): Specifies the file with the secret key in the PEM format.
    • keyfile_password: (optional): Specifies a password for decrypting the keyfile.
    • cafile: (optional): Specifies the file with the CA_BUNDLE with certificates of trusted CAs to use while verifying client certs.
    • ciphers: (optional): Specifies the permitted cipher suites (e.g. “ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES128-GCM-SHA256:!SSLv1:!SSLv2:!SSLv3:!TLSv1:!TLSv1.1”)
    • verify_client: (optional): none (default), optional or required. When none REST API will not check client certificates. When required client certificates are required for all REST API calls. When optional client certificates are required for all unsafe REST API endpoints. When required is used, then client authentication succeeds, if the certificate signature verification succeeds. For optional the client cert will only be checked for PUT, POST, PATCH, and DELETE requests.
    • allowlist: (optional): Specifies the set of hosts that are allowed to call unsafe REST API endpoints. The single element could be a host name, an IP address or a network address using CIDR notation. By default allow all is used. In case if allowlist or allowlist_include_members are set, anything that is not included is rejected.
    • allowlist_include_members: (optional): If set to true it allows accessing unsafe REST API endpoints from other cluster members registered in DCS (IP address or hostname is taken from the members api_url). Be careful, it might happen that OS will use a different IP for outgoing connections.
    • http_extra_headers: (optional): HTTP headers let the REST API server pass additional information with an HTTP response.
    • https_extra_headers: (optional): HTTPS headers let the REST API server pass additional information with an HTTP response when TLS is enabled. This will also pass additional information set in http_extra_headers.

Here is an example of both http_extra_headers and https_extra_headers:

restapi:
  listen: <listen>
  connect_address: <connect_address>
  authentication:
    username: <username>
    password: <password>
  http_extra_headers:
    'X-Frame-Options': 'SAMEORIGIN'
    'X-XSS-Protection': '1; mode=block'
    'X-Content-Type-Options': 'nosniff'
  cafile: <ca file>
  certfile: <cert>
  keyfile: <key>
  https_extra_headers:
    'Strict-Transport-Security': 'max-age=31536000; includeSubDomains'

CTL

  • ctl: (optional)
    • insecure: Allow connections to REST API without verifying SSL certs.
    • cacert: Specifies the file with the CA_BUNDLE file or directory with certificates of trusted CAs to use while verifying REST API SSL certs. If not provided patronictl will use the value provided for REST API “cafile” parameter.
    • certfile: Specifies the file with the client certificate in the PEM format. If not provided patronictl will use the value provided for REST API “certfile” parameter.
    • keyfile: Specifies the file with the client secret key in the PEM format. If not provided patronictl will use the value provided for REST API “keyfile” parameter.

Watchdog

  • mode: off, automatic or required. When off watchdog is disabled. When automatic watchdog will be used if available, but ignored if it is not. When required the node will not become a leader unless watchdog can be successfully enabled.
  • device: Path to watchdog device. Defaults to /dev/watchdog.
  • safety_margin: Number of seconds of safety margin between watchdog triggering and leader key expiration.

Tags

  • nofailover: true or false, controls whether this node is allowed to participate in the leader race and become a leader. Defaults to false
  • clonefrom: true or false. If set to true other nodes might prefer to use this node for bootstrap (take pg_basebackup from). If there are several nodes with clonefrom tag set to true the node to bootstrap from will be chosen randomly. The default value is false.
  • noloadbalance: true or false. If set to true the node will return HTTP Status Code 503 for the GET /replica REST API health-check and therefore will be excluded from the load-balancing. Defaults to false.
  • replicatefrom: The IP address/hostname of another replica. Used to support cascading replication.
  • nosync: true or false. If set to true the node will never be selected as a synchronous replica.

In addition to these predefined tags, you can also add your own ones:

  • key1: true
  • key2: false
  • key3: 1.4
  • key4: "RandomString"

Tags are visible in the REST API and patronictl list You can also check for an instance health using these tags. If the tag isn’t defined for an instance, or if the respective value doesn’t match the querying value, it will return HTTP Status Code 503.