This specifies whether debug output is logged for this particular logger. Also can contain value 'trace', which is highest level of debug messages. off on trace If the *to_logfile* option is set to 'yes', this option specifies the pathname of the log file. This specifies the logfile level for this particular subsystem. Ignored if *debug* is 'on'. alert crit debug emerg err info notice warning This specifies the syslog facility type that will be used for any messages sent to syslog. daemon local0 local1 local2 local3 local4 local5 local6 local7 This specifies the syslog level for this particular subsystem. Ignored if *debug* is 'on'. alert crit debug emerg err info notice warning This specifies whether to use the respective destination of logging output. Please note, if you are using *to_logfile* and want to rotate the file, use `logrotate(8)` with the option `copytruncate`, e.g. ---- /var/log/corosync.log { missingok compress notifempty daily rotate 7 copytruncate } ---- no yes This specifies whether to use the respective destination of logging output. no yes This specifies whether to use the respective destination of logging output. no yes In this configuration section, one can adjust logging. This specifies that file and line should be printed. off on This specifies that the code function name should be printed. off on This specifies that a timestamp is placed on all log messages. off on This specifies the subsystem identity (name) for which logging is specified. This is the name used by a service in the `log_init` call, e.g., 'CPG'. In this configuration section, one can adjust nodes in the cluster. This configuration option is optional when using IPv4 and required when using IPv6. This is a 32bit value specifying the node identifier delivered to the cluster membership service. If this is not specified with IPv4, *nodeid* will be determined from the 32bit IP address the system to which the system is bound with ring identifier of 0. The node identifier value of zero is reserved and should not be used. This specifies IP address of one of the nodes for particular ring as denoted by its number (instead 0, there can be higher numbers). In this configuration section, one can adjust quorum. This enables Downscale feature (see **votequorum**(5)). 0 1 This enables Auto Tie Breaker feature (see **votequorum**(5)). 0 1 This specifies the number of expected votes, overriding the number implied by the number of *node* items within *nodes*. This enables Last Man Standing feature (see **votequorum**(5)). 0 1 This specifies the tunable for Last Man Standing feature (see **votequorum**(5)). This specifies the quorum algorithm to use. As of now, only 'corosync_votequorum' is supported. corosync_votequorum This enables two node cluster operations (see **votequorum**(5)). 0 1 This enables Wait For All feature (see **votequorum**(5)). 0 1 reboot shutdown watchdog none In this configuration section, one can adjust totem protocol. This configuration option is only relevant when no *nodeid* option within *nodelist* section is specified. Some corosync clients require a signed 32bit nodeid that is greater than zero however, by default, corosync uses all 32 bits of the IPv4 address space when generating a nodeid. Set this option to 'yes' to force the high bit to be zero and therefor ensure the nodeid is a positive signed 32bit integer. no yes This specifies the name of cluster and it's used for automatic generating of multicast address. This timeout specifies in milliseconds how long to wait for consensus to be achieved before starting a new round of membership configuration. The minimum value for *consensus* must be 1.2 x *token*. This value will be automatically calculated at 1.2 x *token* if the user doesn't specify a *consensus* value. For two node clusters, a *consensus* larger than the *join* timeout but less than *token* is safe. For three-node or larger clusters, *consensus* should be larger than *token*. There is an increasing risk of odd membership changes, which still guarantee virtual synchrony, as node count grows if *consensus* is less than *token*. This specifies which cipher should be used to encrypt all messages. 3des aes128 aes192 aes256 none 2.0 2.2 This specifies which HMAC authentication should be used to authenticate all messages. none md5 sha1 sha256 sha384 sha512 3des aes128 aes192 aes256 nss This timeout specifies in milliseconds how long to wait before checking that a network interface is back up after it has been downed. This constant specifies how many rotations of the token without receiving any of the messages when messages should be received may occur before a new configuration is formed. Configures the optional HeartBeating mechanism for faster failure detection. Keep in mind that engaging this mechanism in lossy networks could cause faulty loss declaration as the mechanism relies on the network for heartbeating. So as a rule of thumb use this mechanism if you require improved failure in low to medium utilized networks. This constant specifies the number of heartbeat failures the system should tolerate before declaring heartbeat failure, e.g., 3. Also if this value is not set or is 0, the heartbeat mechanism is not engaged in the system and token rotation is the method of failure detection. Zero disables the mechanism. This timeout specifies in milliseconds how long the token should be held by the representative when the protocol is under low utilization. This timeout specifies in milliseconds how long to wait for join messages in the membership protocol. This constant specifies the maximum number of messages that may be sent by one processor on receipt of the token. The *max_messages* parameter is limited to 256000 / *netmtu* to prevent overflow of the kernel transmit buffers. This constant specifies in milliseconds the approximate delay that your network takes to transport one packet from one machine to another. This value is to be set by system engineers and please don't change it if not sure as this effects the failure detection mechanism using heartbeat. This timeout specifies in milliseconds how long to wait before checking for a partition when no multicast traffic is being sent. If multicast traffic is being sent, the merge detection happens automatically as a function of the protocol. This constant defines the maximum number of times on receipt of a token a message is checked for retransmission before a retransmission occurs. This parameter is useful to modify for switches that delay multicast packets compared to unicast packets. The default setting works well for nearly all modern switches. This specifies the network maximum transmit unit. Setting this value beyond '1500', the regular frame MTU, requires ethernet devices that support large, or also called jumbo, frames. If any device in the network doesn't support large frames, the protocol will not operate properly. The hosts must also have their MTU size set from 1500 to whatever frame size is specified here. This specifies the time in milliseconds to check if the failed ring can be auto-recovered. This specifies the mode of redundant ring. Active replication ('active') offers slightly lower latency from transmit to delivery in faulty network environments but with less performance. Passive replication ('passive') may nearly double the speed of the totem protocol if it doesn't become CPU bound. The remaining option is 'none', in which case only one network interface will be used to operate the totem protocol. If only one *interface* section is specified, 'none' is automatically chosen. If multiple *interface* sections are specified, only 'active' or 'passive' may be chosen. The maximum number of *interface* sections that is allowed for either mode ('active' or 'passive') is 2. active none passive This specifies the number of times a problem is detected with multicast before setting the link faulty for 'passive' *rrp_mode*. This variable is unused in 'active' *rrp_mode*. The default is 10 x *rrp_problem_count_threshold*. This specifies the number of times a problem is detected with a link before setting the link faulty. Once a link is set faulty, no more data is transmitted upon it. Also, the problem counter is no longer decremented when the problem count timeout expires. A problem is detected whenever all tokens from the proceeding processor have not been received within the *rrp_token_expired_timeout*. The *rrp_problem_count_threshold* x *rrp_token_expired_timeout* should be at least 50 milliseconds less than the *token* timeout, or a complete reconfiguration may occur. This specifies the time in milliseconds to wait before decrementing the problem count by 1 for a particular ring to ensure a link is not marked faulty for transient network failures. This specifies the time in milliseconds to increment the problem counter for the redundant ring protocol after not having received a token from all rings for a particular processor. This value will automatically be calculated from the *token* timeout and *problem_count_threshold* but may be overridden. This specifies that HMAC/SHA1 authentication should be used to authenticate all messages. It further specifies that all data should be encrypted with the `nss` library and `aes256` encryption algorithm to protect data from eavesdropping. Enabling this option adds an encryption header to every message sent by totem which reduces total throughput. Also encryption and authentication consume extra CPU cycles in corosync. off on This timeout specifies in milliseconds an upper range between 0 and *send_join* to wait before sending a join message. For configurations with less than 32 nodes, this parameter is not necessary. For larger rings, this parameter is necessary to ensure the NIC is not overflowed with join messages on formation of a new ring. A reasonable value for large rings (128 nodes) would be __80__msec. Other timer values must also change if this value is changed. This constant specifies how many rotations of the token without any multicast traffic should occur before the hold timer is started. This timeout specifies a period in milliseconds until a token loss is declared after not receiving a token. This is the time spent detecting a failure of a processor in the current configuration. Reforming a new configuration takes about 50 milliseconds in addition to this timeout. This timeout specifies a period in milliseconds without receiving a token after which the token is retransmitted. This will be automatically calculated if *token* is modified. This value identifies how many token retransmits should be attempted before forming a new configuration. If this value is set, retransmit and hold will be automatically calculated from *retransmits_before_loss* and *token*. This option controls the transport mechanism used. If the interface to which corosync is binding is an RDMA interface such as RoCEE or Infiniband, the 'iba' parameter may be specified. To avoid the use of multicast entirely, a unicast transport parameter 'udpu' can be specified. This requires specifying the list of members that could potentially make up the membership in *nodelist* section before deployment. iba udp udpu This specifies the version of the configuration file. Currently the only valid value for this option is '2'. This option controls the virtual synchrony filter type used to identify a primary component. The preferred choice is YKD dynamic linear voting ('ykd'), however, for clusters larger than 32 nodes YKD consumes a lot of memory. For large scale clusters that are created by changing the MAX_PROCESSORS_COUNT #define in the C code totem.h file, the virtual synchrony filter 'none' is recommended but then AMF and DLCK services (which are currently experimental) are not safe for use. none ykd This constant specifies the maximum number of messages that may be sent on one token rotation. If all processors perform equally well, this value could be large ('300'), which would introduce higher latency from origination to delivery for very large rings. To reduce latency in large rings (16+), the default is a safe compromise. If 1 or more slow processor(s) are present among fast processors, *window_size* should be no larger than 256000 / *netmtu* to avoid overflow of the kernel receive buffers. The user is notified of this by the display of a retransmit list in the notification logs. There is no loss of data, but performance is reduced when these errors occur. This specifies the network address the corosync executive should bind to. *bindnetaddr* should be an IP address configured on the system, or a network address. For example, if the local interface is `192.168.5.92` with netmask `255.255.255.0`, you should set *bindnetaddr* to `192.168.5.92` or `192.168.5.0`. If the local interface is `192.168.5.92` with netmask `255.255.255.192`, set *bindnetaddr* to `192.168.5.92` or `192.168.5.64`, and so forth. This may also be an IPv6 address, in which case IPv6 networking will be used. In this case, the exact address must be specified and there is no automatic selection of the network interface within a specific subnet as with IPv4. If IPv6 networking is used, *nodeid* options within *nodelist* section must be specified. If this is set to 'yes', the broadcast address will be used for communication. If this option is set, *mcastaddr* should not be set. no yes This is the multicast address used by corosync executive. The default should work for most networks, but the network administrator should be queried about a multicast address to use. Avoid `224.x.x.x` because this is a "config" multicast address. This may also be an IPv6 multicast address, in which case IPv6 networking will be used. If IPv6 networking is used, *nodeid* options within *nodelist* section must be specified. It's not needed to use this option if *cluster_name* option in *totem* section is used. If both options are used, *mcastaddr* has higher priority. This specifies the UDP port number. It is possible to use the same multicast address on a network with the corosync services configured for different UDP ports. Please note corosync uses two UDP ports *mcastport* (for mcast receives) and *mcastport* - 1 (for mcast sends). If you have multiple clusters on the same network using the same *mcastaddr*, please configure the **mcastport**s with a gap. This specifies the ring number for the interface. When using the redundant ring protocol, each interface should specify separate ring numbers to uniquely identify to the membership protocol which interface to use for which redundant ring. The *ringnumber* must start at '0'. This specifies the Time To Live (TTL). If you run your cluster on a routed network, the default of '1' will be too small. This option provides a way to increase this up to '255'. The valid range is '0..255'.