# Services ## Introduction Squirro consists of several services that are started and stopped individually. A detailed list of Squirro services is listed later on this page. When a Squirro server is started, all the services are started automatically using the Linux `init.d` subsystem. ## Interacting With Services Services are controlled with the `service` command on the Linux console. See [Accessing Servers](accessing-servers.md#admin-access) for more information. The service command must be run as root. This can be done 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: ```shell-session [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. ```shell-session [root@localhost ~]# service sqtopicd start Starting sqtopicd: [ OK ] ``` ### Stop Service ```shell-session [root@localhost ~]# service sqtopicd stop Stopping sqtopicd: [ OK ] ``` If you now execute the `status` sub-command, it will report the service as being stopped. ```shell-session [root@localhost ~]# service sqtopicd status sqtopicd is stopped ``` ### Restart Service The `restart` sub-command attempts to stop a service first and will then start it again. ```shell-session [root@localhost ~]# service sqtopicd restart Stopping sqtopicd: [ OK ] Starting sqtopicd: [ OK ] ``` ### Services List 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. | | mariadb | 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-cache | NoSQL database used for cache | | redis-server | NoSQL database | | sqclusterd | Controls the multi-cluster setup of Squirro. Removed in version 3.16.2. | | sqconfigurationd | Manages application configuration. | | sqcontentd | Extracts relevant content from web pages. See [Noise Removal](../../data-processing/pipeline-steps/enrich/noise-removal.md#pipeline-steps-noise-removal) within [Data Processing Pipeline](../../data-processing/index.md#data-processing). | | sqdatasourced | Manages data loading process. See [Data Loading](../../data-loading/index.md#data-loading). | | sqdigestmailerd | | | sqemailsenderd | Sends out emails on behalf of Squirro. | | sqfilteringd | Handles search tagging rules. See [Search Tagging and Alerting](../../data-processing/pipeline-steps/index/search-tagging.md#pipeline-steps-search-tagging) within [Data Processing Pipeline](../../data-processing/index.md#data-processing). | | sqfrontendd | Frontend service, implementing the main web interface of Squirro. | | sqingesterd | Refers to the Pipeline service. Manages the process of enriching and indexing data. See [Built-In Steps](../../data-processing/pipeline-steps/index.md#data-processing-pipeline-steps) within [Data Processing Pipeline](../../data-processing/index.md#data-processing). | | sqmachinelearningd | | | sqplumberd | Executes pipelets as part of the pipeline. See [Pipelets](../../pipelets/index.md#pipelets). | | sqproviderd | Endpoint for the providers to import data into the system. See [Data Connectors](../../data-loading/connectors/index.md#data-loading-connectors). | | sqschedulerd | Executes scheduled jobs that the Squirro application needs to run. | | sqthumblerd | Calculates thumbnails for item images that are displayed in Squirro. | | sqtopicd | The topic endpoint of the API for handling data queries. See [APIs and SDKs](../../api/index.md#api). | | sqtopicproxyd | Internal web service access to some project metadata. | | squserd | The endpoint for user management and authentication. See [Authentication](../../api/authentication.md#api-authentication). | | squserproxyd | Internal web service access to some user data. | | sqwebshotd | Analyzes web stories and identifies the most relevant image to use for visualization. | ### NLP Services The following services are part of the NLP service, which a standard Squirro deployment does not include. In large production deployments, the NLP service typically runs on a separate server or cluster from the core Squirro services. Like the standard services, you control these services with the `service` command. | Name | Description | | --- | --- | | sqcross-encoderd | Scores query-paragraph text pairs using a cross-encoder transformer model to rerank search results by relevance. Used by the reranker scoring plugin in cognitive search and question-answering pipelines. | | sqquestion-answeringd | Runs a transformer model that extracts answers to natural language questions from indexed content. Used by question-answering pipelines. | | sqsentence-embeddingsd | Generates vector embeddings for text using a transformer model. Used for semantic search and other embedding-based features. |