go.etcd.io/etcd@v3.3.27+incompatible/Documentation/learning/glossary.md (about)

     1  ---
     2  title: Glossary
     3  ---
     4  
     5  This document defines the various terms used in etcd documentation, command line and source code.
     6  
     7  ## Alarm
     8  
     9  The etcd server raises an alarm whenever the cluster needs operator intervention to remain reliable.
    10  
    11  ## Authentication
    12  
    13  Authentication manages user access permissions for etcd resources.
    14  
    15  ## Client
    16  
    17  A client connects to the etcd cluster to issue service requests such as fetching key-value pairs, writing data, or watching for updates.
    18  
    19  ## Cluster
    20  
    21  Cluster consists of several members.
    22  
    23  The node in each member follows raft consensus protocol to replicate logs. Cluster receives proposals from members, commits them and apply to local store.
    24  
    25  ## Compaction
    26  
    27  Compaction discards all etcd event history and superseded keys prior to a given revision. It is used to reclaim storage space in the etcd backend database.
    28  
    29  ## Election
    30  
    31  The etcd cluster holds elections among its members to choose a leader as part of the raft consensus protocol.
    32  
    33  ## Endpoint
    34  
    35  A URL pointing to an etcd service or resource.
    36  
    37  ## Key
    38  
    39  A user-defined identifier for storing and retrieving user-defined values in etcd.
    40  
    41  ## Key range
    42  
    43  A set of keys containing either an individual key, a lexical interval for all x such that a < x <= b, or all keys greater than a given key.
    44  
    45  ## Keyspace
    46  
    47  The set of all keys in an etcd cluster.
    48  
    49  ## Lease
    50  
    51  A short-lived renewable contract that deletes keys associated with it on its expiry.
    52  
    53  ## Member
    54  
    55  A logical etcd server that participates in serving an etcd cluster.
    56  
    57  ## Modification Revision
    58  
    59  The first revision to hold the last write to a given key.
    60  
    61  ## Peer
    62  
    63  Peer is another member of the same cluster.
    64  
    65  ## Proposal
    66  
    67  A proposal is a request (for example a write request, a configuration change request) that needs to go through raft protocol.
    68  
    69  ## Quorum
    70  
    71  The number of active members needed for consensus to modify the cluster state. etcd requires a member majority to reach quorum.
    72  
    73  ## Revision
    74  
    75  A 64-bit cluster-wide counter that is incremented each time the keyspace is modified.
    76  
    77  ## Role
    78  
    79  A unit of permissions over a set of key ranges which may be granted to a set of users for access control.
    80  
    81  ## Snapshot
    82  
    83  A point-in-time backup of the etcd cluster state.
    84  
    85  ## Store
    86  
    87  The physical storage backing the cluster keyspace.
    88  
    89  ## Transaction
    90  
    91  An atomically executed set of operations. All modified keys in a transaction share the same modification revision.
    92  
    93  ## Key Version
    94  
    95  The number of writes to a key since it was created, starting at 1. The version of a nonexistent or deleted key is 0.
    96  
    97  ## Watcher
    98  
    99  A client opens a watcher to observe updates on a given key range.