Configuring Presto-Admin
A Presto cluster consists of a coordinator node and one or more workers nodes. A coordinator and worker may be located on the same node, meaning that you can have a single-node installation of Presto, but having a dedicated node for the coordinator is recommended for better performance, especially on larger clusters.
In order to use presto-admin
to manage software on a cluster of nodes,
you must specify a configuration for presto-admin
. This configuration
indicates the nodes on which to install as well as other credentials.
To set up a configuration, create a file ~/.prestoadmin/config.json
(or $PRESTO_ADMIN_CONFIG_DIR/config.json
if you have the presto-admin
config directory set using the environment variable) with the content below as
appropriate for your cluster setup. Replace the variables denoted with
brackets <> with actual values enclosed in double quotations. The user
specified by username
must have sudo access, unless the username
is root, on all the Presto nodes, and presto-admin
also must be
able to login to all of the nodes via SSH as that user (see
SSH Configuration for details on how to set that up). The
file should be owned by root with R/W permissions (i.e. 622).
Note
The sudo setup for a non-root user must have the ability to run /bin/bash as root. This can be a security issue. The IT organization should take the necessary steps to address this security hole and select an appropriate presto-admin user.
Configuration for Amazon EMR
Use the following configuration as a template for Amazon EMR:
{
"username": "hadoop",
"port": "<ssh_port>",
"coordinator": "<EMR_master_node_host_name>",
"workers": ["<host_name_1>", "<host_name_2>", ... "<host_name_n>"],
"java8_home":"<path/to/java8/on/presto/nodes>"
}
Also, for running Presto Admin commands on Amazon EMR, do the following:
Copy the
.pem
file associated with the Amazon EC2 key pair to the Presto Admin installation node of the EMR cluster.Use the
-i </path/to/your.pem>
input argument when running presto-admin commands on the node.</path/to/presto-admin> -i </path/to/your.pem> <presto_admin_command>
Configuration for other clusters
Use the following configuration as a template for other clusters:
{
"username": "<ssh_user_name>",
"port": "<ssh_port>",
"coordinator": "<host_name>",
"workers": ["<host_name_1>", "<host_name_2>", ... "<host_name_n>"],
"java8_home":"<path/to/java8/on/presto/nodes>"
}
All of the properties are optional, and if left out the following defaults will be used:
{
"username": "root",
"port": "22",
"coordinator": "localhost",
"workers": ["localhost"]
}
Note that java8_home
is not set by default. It only needs to be set if
Java 8 is in a non-standard location on the Presto nodes. The property is used
to tell the Presto RPM where to find Java 8.
Note
If you have installed the JDK, java8_home
should be set so refer to the jre
subdirectory of the JDK.
You can also specify some but not all of the properties. For example, the
default configuration is for a single-node installation of Presto on the same
node that presto-admin
is installed on. For a 6 node cluster with default
username and port, a sample config.json
would be:
{
"coordinator": "master",
"workers": ["slave1","slave2","slave3","slave4","slave5"]
}
You can specify a range of workers by including the number range in brackets in the worker name. For example:
"workers": ["worker[01-03]"]
is the same as
"workers": ["worker01", "worker02", "worker03"]
Sudo Password Specification
Please note that if the username you specify is not root, and that user needs to specify a sudo password, you do so in one of two ways. You can specify it on the command line:
./presto-admin <command> -p <password>
Alternatively, you can opt to use an interactive password prompt, which prompts you for the initial value of your password before running any commands:
./presto-admin <command> -I
Initial value for env.password: <type your password here>
The sudo password for the user must be the same as the SSH password.