Service Discovery

Which interface would you use to register a service dynamically using standard tools like 'curl'?

A DevOps engineer is configuring a Consul service `payment-processor` that must be discoverable only when its health check is passing. The service is registered with a script health check that runs every 10 seconds. The engineer wants to ensure that DNS queries for `payment-processor` return only healthy instances. Which two actions should the engineer take? (Choose two.)

A Consul operator observes that a web service registered on two nodes is only reachable through the DNS interface on one node. The service definition on both nodes is identical, including the same service name and port. What is the most likely cause?

You need to register a health check that triggers an alert when memory usage is high. Which type of check is most appropriate?

A Consul operator is using the HTTP API to register a web service with an external health check script. The operator wants to ensure that if the service process fails but the node remains up, the service is marked unhealthy and removed from DNS query results. Which of the following API endpoints should the operator use to register the service and its check together?

A service definition includes a 'meta' block. What is the intended use of this block?

A Consul cluster has three server nodes and multiple client agents. A service 'db' is registered on two nodes, each with a health check that includes 'DeregisterCriticalServiceAfter' set to '1h'. One of the nodes experiences a network partition and becomes unreachable. After 2 hours, the node rejoins the cluster. What happens to the service instance on that node?

Which THREE of the following are valid check types in Consul?

You need to verify if a node has successfully joined the cluster for service discovery. Which tool confirms this?

Which THREE of the following are valid ways to register a service in Consul?

What is the impact of setting 'enable_tag_override' to true in a service definition?

When using Consul DNS for a service, what happens if no instances are healthy?

Which TWO of the following are true regarding the Consul Service Catalog?

When a service check transitions to 'critical', what does Consul do with the service's DNS entry?

An operator wants to query the Consul catalog for all nodes that provide a service named `api` in the `us-east` datacenter. They need to retrieve the node names and addresses. Which Consul HTTP API endpoint should they use?

A developer runs `dig @127.0.0.1 -p 8600 web.service.consul SRV` and receives no records, even though `consul catalog services` lists `web` and `consul members` shows the node as alive. A health check for the `web` service is registered and currently shows a critical status. What is the most likely cause of the empty SRV response?

Which TWO of the following are standard DNS records returned by Consul for service discovery?

When multiple agents are in a cluster, how does Consul ensure that service discovery information is consistent across all nodes?

A platform engineer is adding a new service to Consul. The service must appear in the catalog with the name 'billing', be reachable over DNS at billing.service.consul, and be associated with the tag 'prod'. Which registration block correctly achieves this when using the HTTP API?

A Consul operator needs to deregister a specific service instance named 'web-01' from a node without affecting other instances of the same service. The service was registered with the ID 'web-01'. Which action accomplishes this?

A developer needs to register a service named 'api' with Consul and ensure that it is only discoverable by consumers that explicitly request the 'v2' tag. Which Consul feature should be used?

Which TWO of the following statements are true about the 'passing' parameter in DNS queries?

A Consul cluster is used for service discovery across multiple datacenters. A service named 'api' is registered in both datacenter 'dc1' and 'dc2'. A client in 'dc1' needs to discover instances of 'api' in 'dc2' using DNS. Which DNS query format should the client use?

An administrator needs to query service information. Which DNS record type is commonly used by Consul to return service addresses?

What is the purpose of the 'service-tag' in a Consul service definition?

A service is intermittently failing to resolve via DNS because it has multiple health checks, some of which are 'warning'. How do you ensure it is only returned when all checks are 'passing'?

Which THREE of the following are valid ways to categorize services in Consul?

An operator registers a service 'cache' with an HTTP health check pointing to https://10.0.0.5:8443/health. The service appears in the catalog, but DNS queries for cache.service.consul return no records, and the check status shows critical with the message 'Get https://10.0.0.5:8443/health: x509: certificate signed by unknown authority'. Which action resolves the issue while keeping the check functional?

You have a service that requires specific routing logic based on the environment. How can you distinguish between 'production' and 'staging' instances of the same service name using metadata?

A DevOps engineer needs to register an external service that runs outside the Consul datacenter, such as a third-party API. The service has a static IP address and a known port. Which Consul feature should be used to make this service discoverable within Consul?

An operator registers a service with a TTL health check. The service is responsible for updating the check status via the HTTP API. The service fails to send updates for 90 seconds. The check is configured with 'DeregisterCriticalServiceAfter' set to 10 minutes. What is the current health status of the service, and what will happen after 10 minutes?

Which TWO of the following actions occur when a node fails in a Consul cluster?

A developer registers a service 'web-frontend' with Consul using the HTTP API. The service registration includes a health check with a TCP check on port 8080 and an interval of '15s'. After registration, the developer queries the service using the DNS interface: 'dig @127.0.0.1 -p 8600 web-frontend.service.consul'. The query returns no results. Which of the following is the most likely reason?

Which of the following best describes the 'consul agent -dev' mode in relation to service discovery?

An operator registers a web service with Consul using the HTTP API. The registration includes a TTL health check with a 30-second interval, but the application code does not yet call the pass endpoint. Shortly after registration, the service disappears from healthy DNS results. What is the most likely reason?

A Consul cluster spans multiple datacenters. A service `user-auth` is registered in both `dc1` and `dc2`. A client in `dc1` queries the DNS interface for `user-auth.service.consul`. By default, which instances will be returned?

Which command is used to check the status of a registered service?

Which THREE of the following are key components of a service definition?

A service is registered with Consul using the HTTP API, but it is not appearing in DNS queries. The service definition includes a health check that is currently critical. What is the most likely reason for the DNS query failure?

What is the effect of changing the 'interval' parameter in a service health check?

Which THREE of the following are benefits of using the Consul DNS interface?

A developer registers a service named 'orders' on a Consul node and wants DNS queries for orders.service.consul to return the service's SRV records so clients can discover both the address and the port. The developer is verifying that the registration contains everything needed for SRV resolution. Which two registration elements must be present for SRV queries to return usable records? (Choose two.)

A Consul operator is troubleshooting a service that intermittently disappears from the catalog. The service is registered with a TTL health check that is updated every 30 seconds by a script. The operator notices that the service is marked as critical and then deregistered. Which configuration change should the operator make to prevent the service from being deregistered?