getHostsV1.md

getHosts: Gets the hosts in a cluster

This command gets the number hosts and the IP address of each host in an Exasol cluster.

:warning: This command was designed to be used for creating subconnections using enterParallel which has been deprecated. The IP addresses returned by this command may not be correct if the prerequisites for subconnections using enterParallel are not fulfilled. Namely, all active database nodes must have a uniform distance between the private and public IP addresses.

For example, a database with private IP addresses [10.168.1.1, 10.168.1.2, 10.168.1.3] and public IP addresses [192.168.10.101, 192.168.10.102, 192.168.10.103] fulfills this requirement because the distance between the private and public IP addresses is the same for each node. However, a database with private IP addresses [10.168.1.1, 10.168.1.2, 10.168.1.3] and public IP addresses [192.168.10.101, 192.168.10.102, 192.168.10.104] does not fulfill this requirement because the distance between the private and public IP addresses is not the same for each node.

Request fields:

• command (string) => command name: "getHosts"
• attributes (object, optional) => attributes to set for the connection (see Attributes)
• hostIp (string) => IP address of the Exasol host to which the client is currently connected (i.e., the Exasol host used to create the connection; e.g., ws://<hostIp>:8563)

Request JSON format

 {
     "command": "getHosts",
     "attributes": {
             // as defined separately
     },
     "hostIp": <string>
 }

Response fields:

• status (string) => command status: "ok" or "error"
• responseData (object, optional) => only present if status is "ok"
  • numNodes (number) => number of nodes in the cluster
  • nodes (string[]) => array of cluster node IP addresses
• exception (object, optional) => only present if status is "error"
  • text (string) => exception message which provides error details
  • sqlCode (string) => five-character exception code if known, otherwise "00000"

Response JSON format

 {
     "status": <"ok" | "error">,
     // in case of "ok"
     "responseData": {
             "numNodes": <number>,
             "nodes": [
                     <string>
             ]
     },
     // in case of "error"
     "exception": {
             "text": <string>,
             "sqlCode": <string>
     }
 }