#MIN AND MON HOW TO#

Updates on the Ceph Monitor, changes to the monmap always run through aĭistributed consensus algorithm called Paxos. Strict consistency also applies to updates to the monmap. Monmaps for discovery and they share monmaps with clients and other Cephĭaemons, the monmap provides monitors with a strict guarantee that their In nf when specifying a monitor address or port). Using the monmap instead of theĬeph configuration file avoids errors that could break the cluster (e.g., typos Other Ceph Monitors in the Ceph Storage Cluster. Other using the monitor map (monmap), not the Ceph configuration file.Ī Ceph Monitor always refers to the local copy of the monmap when discovering Use the Ceph configuration file to discover monitors, monitors discover each Whereas, Ceph Clients and other Ceph daemons Strict consistency requirements for a Ceph monitor when discovering anotherĬeph Monitor within the cluster. When you add monitor settings to your Ceph configuration file, you need to beĪware of some of the architectural aspects of Ceph Monitors.

When a Ceph Storage Cluster runs multiple Ceph Monitors for high availability,Ĭeph Monitors use Paxos to establish consensus about the master cluster map.Ī consensus requires a majority of monitors running to establish a quorum forĬonsensus about the cluster map (e.g., 1 2 out of 3 3 out of 5 4 out of 6 įorce monitor to join quorum even if it has been previously removed

ToĮnsure high availability in a production Ceph Storage Cluster, you should runĬeph with multiple monitors so that the failure of a single monitor WILL NOT Single monitor however, a single monitor is a single-point-of-failure. Provides for one monitor in the test cluster. Our Configuring ceph section provides a trivial Ceph configuration file that See Monitoring a ClusterĪnd Monitoring OSDs and PGs for additional details. Important part of your system administration duties. When operating your Ceph Storage Cluster, keeping track of these states is an Map each maintain a history of their map versions. The monitor map, OSD map, placement group map and metadata server When there is a significant change in the state of the cluster–e.g., a Ceph OSDĭaemon goes down, a placement group falls into a degraded state, etc.–theĬluster map gets updated to reflect the current state of the cluster.Īdditionally, the Ceph Monitor also maintains a history of the prior states of State of the cluster such as the total amount of storage space, and the amount Or down whether, the placement groups are active or inactive, andĬlean or in some other state and, other details that reflect the current Which processes that are in the Ceph Storage Cluster are up and running Number of important things: which processes are in the Ceph Storage Cluster The placement group map and the metadata server map. The cluster map is a composite of maps, including the monitor map, the OSD map, In Ceph versions 0.58 and earlier, Ceph Monitors use a Paxos instance forĮach service and store the map as a file. (using leveldb) to perform store-wide synchronization.

Ceph Monitors leverage the key/value store’s snapshots and iterators Monitors can query the most recent version of the cluster map during sync Monitors write all changes in the monitor services to a single Paxos instance,Īnd Paxos writes the changes to a key/value store for strong consistency. Ceph Monitors also provide authentication and logging services. The primary role of the Ceph Monitor is to maintain a master copy of the cluster Scalability and High Availability for additional details. Very important aspect of Ceph’s high scalability and performance. Locations allows a Ceph Client to talk directly to Ceph OSD Daemons, which is a With a current copy of the cluster map and the CRUSH algorithm, a CephĬlient can compute the location for any object. Before Ceph Clients can read from or write toĬeph OSD Daemons or Ceph Metadata Servers, they must connect to a Ceph Monitorįirst. Background Ĭeph Monitors maintain a “master copy” of the Cluster Map, which means aĬeph Client can determine the location of all Ceph Monitors, Ceph OSDĭaemons, and Ceph Metadata Servers just by connecting to one Ceph Monitor and SeeĪdding/Removing a Monitor for details. The monitor complement usually remains fairlyĬonsistent, but you can add, remove or replace a monitor in a cluster.

#MIN AND MON HOW TO#

Understanding how to configure a Ceph Monitor is an important part ofīuilding a reliable Ceph Storage Cluster. Report a Documentation Bug Monitor Config Reference 

Min and mon