ConfD

ConfD is a low-level API that is used to administer an Exasol database. All administrative actions can be performed using ConfD.

ConfD abstracts the administration and configuration tasks into jobs, which take parameters. These jobs are executed directly on the database nodes. The only way to interact with ConfD directly is to connect to the node. For more information, see Running ConfD Jobs.

ConfD jobs are then orchestrated into a scheduler that eventually executes all of the jobs. The ConfD scheduler executes and manages the jobs in an asynchronous way. Every job has its own pipeline, in which several stages are defined:

• submitted: they received a job ID and are now waiting in the queue to be scheduled.

• scheduled: the scheduler has examined the job, accepted (or declined) it, assigned it a new EXAConf revision (if necessary) and started execution (in a dedicated worker thread).

• executed: the commands are being executed (a job may consist of multiple commands). Each command is documented in its own section within the job file (including result and output).

• finished: all commands of the job have been executed and stored within the job file. This is the last stage for a read-only job.

• committed: all nodes have received the changes made by this job and the new EXAConf has been synchronized. This is the last stage of a modify job.

Once a job is submitted, the ConfD scheduler takes over and saves the result for this job at different stages, and marks the job as “finished” when the task on the final stage is done. Clients that submit a job can then query the result according to the job ID at that moment. The client can do additional actions while the job is being executed, or wait for the results from the job.

Authentication

ConfD supports basic authentication with a user and password. During deployment, the user admin is created with the password specified from the CCC_PLAY_ADMIN_PASSWORD parameter in c4. If the password is not known, change the password using the ConfD job user_passwd or by creating a new user. For more details, see Add Users. In these cases, use confd_client instead of XML-RPC to avoid having to authenticate with a new user.

When creating a new user, assign the user to the exaadm group.

Running ConfD Jobs

ConfD is available on every database node. You can interact with ConfD using confd_client or XML-RPC. ConfD jobs and parameters are the same regardless of if you use confd_client or XML-RPC.

The examples in the documentation use confd_client. However, you can convert the confd_client commands into an XML-RPC command if you prefer to use that interface.

Command-line using confd_client

confd_client is a command-line tool that is available on every database node. This tool lets you interact with ConfD directly in a terminal. To use confd_client, log into the database access node using c4 and open confd_client:

c4 connect -t1/cos

confd_client --help

The user executing all of the ConfD jobs with confd_client is the user who is logged in to the node. In most cases, this is root. There is no extra authentication step when using confd_client in this way.

confd_client accepts different formats to run a job. For more information, consult the help file from the command above. In general, these commands are identical and perform the same action. In the example below, the ConfD job db_start is executed with the parameter db_name:

confd_client -c db_start -a 'db_name: Exasol'

The above format is only available for jobs using one parameter.

confd_client -c db_start -a '{db_name: Exasol}'

confd_client db_start db_name: Exasol

The above format also includes auto-completion for both job names and parameter names.

XML-RPC using Python

You can also interact with ConfD using an XML-RPC interface in Python. When using XML-RPC, you must authenticate with a user. For more details, see Authentication.

To connect to ConfD, enter the IP address of the database access node (found using c4 ps on the terminal) and the user's credentials. By default, the XML-RPC interface is available on port 20003. For example:

import xmlrpc.client
import requests, urllib3, ssl
import sys
import json
import pprint

# Disable SSL warnings
urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)

# Fill in any database host, the user and password for the user
database_host = '203.0.113.78:20003' # Enter the IP address of the database access node. By default, use port 20003
user = 'admin' # Enter the username you are connecting with
pw = 'exasol' # Enter the password for that user

connection_string = f'https://{user}:{pw}@{database_host}'

sslcontext = ssl._create_unverified_context()

# Establish connection 
conn = xmlrpc.client.ServerProxy(connection_string, context = sslcontext, allow_none=True)

Once you are connected, you can execute a job:

# Choose the job you want to run.
job_name = 'db_start'
# Set the parameters for the chosen job
params = {'db_name': 'Exasol'}

# Execute a job immediately and waits for it to finish and returns the result
conn.job_exec(job_name, {'params': params})

For more examples on how you can interact with ConfD in XML-RPC, see the confd_xmlrpc script on GitHub.

ConfD Jobs

BucketFS Jobs

Database Jobs

Group Jobs

Infrastructure Jobs

License Jobs

Node Jobs

Object Volume Jobs

Other Jobs

Plugin Jobs

Remote Volume Jobs

Storage Jobs

User Jobs