Perform low-level maintenance on your core system, access the database and carry out Elasticsearch queries.

Introduction

The Commander service for yuuvis® allows you as a DevOp to perform low-level maintenance on your core system. You can adjust the differences between the DBMS, Elasticsearch, and your repository. You can access the database and carry out Elasticsearch queries to ,e.g., rebuild the full-text index from the database. The Commander service itself does not support a REST interface of its own, but a connection via Secure Shell (SSH) instead. Thus, the Commander service provides a SSH server at runtime. If you are connected to an SSH client, you can execute predefined commands with self-imposed parameters.

Commander Set Up

To use the Commander service, an SSH connection is required. The recommended parameters for the configuration of the SSH connection are given in this section.

Port Redirection

The Commander Service starts the SSH server per default on port 8022. If there are pods in the Kubernetes final destination platform, a forwarding has to be started for port 8022.

localhost@root:~$ kubectl port-forward -n sanity commander-0000000000-00000 8022

Connecting to SSH Client

Since the connection has to persist during long-term operations without user interactions, keepalives should be enabled. Furthermore, the Commander output might contain important information and thus should be stored in a file.

Setup under Windows

Under a Windows operating system, the usage of PuTTY is recommended. The screenshot below shows the recommended PuTTY configuration enabling the keepalives on the left, and activating the output in a file on the right. 

Setup under Linux

The standard SSH client can be used. The keepalive function can be activated with the option "ServerAliveInterval 20". The output in a file can be achieved by forwarding to the tee command.

localhost@root:~$ ssh -o "ServerAliveInterval 20" -l root -p 8022 127.0.0.1 2>&1 | tee commander-output.log

Executing Commands

The command help lists all available commands that are provided in addition to the actuator endpoint.

If one of the commands is entered, a list of the available sub-commands is returned.

Help information is available for every single sub-command. It is provided by the respective command with the appended parameter -h.

Available Commands

• Cleanup of the Audit Trail

• Reindexing of Elasticsearch from Database

• Comparing Elasticsearch and Database
• Searching for Content Files without Object Reference

Summary

This article introduced the Commander service and its functionality for yuuvis® Momentum. The available commands enable maintenance in different situations such as cleaning up the audit trail.