Obserbability helps in monitoring and the main advantage is it helps identifing the cause of the issues that occurs and in reducing/fixing the issue.
Monitoring just monitor the infra/logs/application or what we have configured and will notify in case of any issue. Whereas Obserbability helps in monitoring and troubleshooting via idenfying the root cause.
Datadog is a monitoring tool to monitor the performance of application and infra. It is SAAS platform.
Datadog Agent is an agent that runs in the servers and collects the information (events,alerts) and send to the DATADOG
It has 3compnents:
1:- collecteor :- It collect infra related logs/events (cpu, memory,Disk usage etc) . Send the details to Fowarder via TCP 17123 port
2:- Dog StatsD :- It collect Application related logs. Send the details to Fowarder via TCP 17123 port
3:- Forwarder :- Forward the events to DataDog