Table of Contents
Introduction
Squirro consists of several services that are started and stopped individually. The Overview section talks a bit about those components. A detailed list of the services is available below.
When a Squirro server is started, all the services are started automatically using the Linux initd subsystem.
Interacting with services
Services are controlled with the service command on the Linux console. The service command must be run as root. This can be achieved by either becoming root first (using sudo -i) or by prefixing every service command with the sudo command.
The first argument for the command is the service name to interact with, then the operation to execute.
Check service status
The service status is returned with the status sub-command. For example:
[root@localhost ~]# service sqtopicd status sqtopicd (pid 3164) is running...
Start service
If a service is not running, the start sub-command can be used to launch it.
[root@localhost ~]# service sqtopicd start Starting sqtopicd: [ OK ]
Stop service
[root@localhost ~]# service sqtopicd stop Stopping sqtopicd: [ OK ]
If you now execute the status sub-command, it will report the service as being stopped.
[root@localhost ~]# service sqtopicd status sqtopicd is stopped
By default Squirro ships with Monit to automatically start services again that have been stopped. In that case it may appear that the service is not being stopped. Monit can be stopped separately using the command service monit stop.
Restart service
The restart sub-command attempts to stop a service first and will then start it again.
[root@localhost ~]# service sqtopicd restart Stopping sqtopicd: [ OK ] Starting sqtopicd: [ OK ]
Services
The following services form part of Squirro or are built-in services that Squirro uses. They can all be controlled with the service command as shown in the previous section.
| Name | Description |
|---|---|
| crond | Task runner that executed scheduled tasks regularly. |
| elasticsearch | Main data storage for indexed data. |
| monit | Service monitor used to automatically start services again when they are stopped. |
| mysqld | Relational database used for storage of metadata about Squirro projects. |
| nginx | Web server through which all the requests for the frontend and the Squirro services are served. |
| redis-server | NoSQL database used for caching. |
| sqbulkd | Bulk importing of data. |
| sqcachecleansingd | Cleans the Varnish cache when data changes. |
| sqclusterd | Controls multi-cluster setup of Squirro. See Clustering. |
| sqconfigurationd | Manages application configuration. See Configuration Reference. |
| sqcontentd | Extracts relevant content from web pages. See Noise Removal in the Data Loading and Processing manual. |
| sqfeedd | Data provider for feeds. See Feed Provider in the Data Loading and Processing manual. |
| sqfileimportd | Used to import CSV data through the web interface. |
| sqfilteringd | Handles search tagging rules. See Search Tagging in the Data Loading and Processing manual. |
| sqfingerprintd | Manages the fingerprints (Smart Filters). |
| sqfrontendd | Frontend service, implementing the main web interface of Squirro. |
| sqpipelined | Pipeline service. Manages the process of enriching and indexing data. See Data Enrichment in the Data Loading and Processing manual. |
| sqplumberd | Executes pipelets as part of the pipeline. See Pipelets in the Data Loading and Processing manual. |
| sqproviderd | Endpoint for the providers to import data into the system. See Providers in the Data Loading and Processing manual. |
| sqrelatedstoryd | Detects near-duplicates as part of the pipeline. See Near-Duplicate Detection in the Data Loading and Processing manual. |
| sqschedulerd | Executes scheduled jobs that the Squirro application needs to run. |
| sqsourcerd | Finds data sources for input criteria, such as a query or a web site URL. |
| sqsquirreld | Web crawler component. |
| sqthumblerd | Calculates thumbnails for item images that are displayed in Squirro. |
| sqtopicd | Endpoint for the Squirro API. See Working with Entities in the API Reference. |
| sqtopicproxyd | Internal web service access to some project metadata. |
| squserd | Endpoint for user management and authentication. See Authentication in the Reference manual. |
| squserproxyd | Internal web service access to some user data. |
| sqwebshotd | Analyzes web stories and identifies the most relevant image to use for visualization. |
| varnish | Caching web proxy. Configured to sit in front of nginx. |