You are troubleshooting why a service registered via HTTP API is not showing up in the catalog. Which tool provides the most immediate insight into the registration status?
Which Consul feature allows you to perform health checks against a service that does not have an exposed HTTP endpoint but resides on the same machine?
An administrator wants to register a service using a JSON file. Where should this file be placed on a standard Consul agent installation to ensure automatic loading?
You need to ensure that a service is only discoverable via DNS if it passes its health checks. Which configuration setting in the service definition achieves this?
A platform team runs a Consul cluster in production. They want to prevent a specific service, `redis-cache`, from being returned by DNS queries and catalog lookups unless it has passed its health check. They have already configured a TTL health check for the service. What must they do to ensure the service is only discoverable when healthy?
A Consul operator needs to register an external service (a third-party API) into the Consul catalog so that internal applications can discover it alongside other services. The external service does not run a Consul agent. Which Consul feature should the operator use?
A developer registers a web service `api-gateway` on a Consul node using the HTTP API. The service definition includes a `meta` block with `version` and `environment` keys. Later, the developer queries the service catalog and notices that the `meta` fields are not returned in the response. What is the most likely reason for the missing metadata?
A developer registers a new service instance with the local Consul agent using the HTTP API. The registration includes a TCP health check on port 8080. The service process is running and listening on port 8080, but the check status remains 'critical'. The developer confirms the port is open using netcat from the same host. What is the most likely cause?
A Consul operator is configuring a service registration in a JSON file to be loaded by a Consul agent. The operator wants to ensure that the service is discoverable via DNS and that clients can filter instances by environment tag. The service should also have a health check that verifies the service is responding on port 8080. Which TWO of the following configuration fields are required to achieve this? (Choose two.)
A developer is using the Consul DNS interface to discover instances of the `web` service. They want to retrieve only the instances that are healthy and have the tag `v1`. Which DNS query format should they use?
A platform team is designing a service discovery solution using Consul. They need to ensure that when a service instance becomes unhealthy, it is automatically removed from DNS query results and that clients can still discover other healthy instances. Which two configurations or behaviors achieve this? (Choose two.)
A developer registers a web service with the Consul catalog using the HTTP API. The service definition includes a TCP check on port 8080. The service process is running and listening on port 8080, but the service appears as critical in the Consul UI. Which command will provide the most immediate insight into why the health check is failing?
A Consul operator needs to deregister a service instance `web-01` from the catalog immediately after the service process stops. The service is registered with a TTL health check. Which configuration should the operator use to ensure the service is removed promptly when the process terminates?
A Consul operator needs to register a service that is only accessible via a Unix domain socket on the same host. The service does not listen on any TCP port. Which Consul service definition field should be used to specify the socket path for health checking?
A developer needs to retrieve the IP address and port of all healthy instances of the 'web' service using Consul's DNS interface. The Consul DNS server is listening on the default port. Which of the following DNS queries will return only the healthy instances?
A platform team runs a Consul cluster with two datacenters, dc1 and dc2, joined via WAN gossip. A service named 'payments' is registered only in dc2. An operator in dc1 queries the DNS interface with 'dig payments.service.consul' and receives NXDOMAIN. The operator wants the same query to return the healthy instances from dc2 without changing the service name. Which query should the operator use?
A service is registered in Consul with an HTTP health check that returns a 500 status code. The service itself is functioning correctly, but the check is failing. Which Consul CLI command will show the output of the health check, including the HTTP status code?
A Consul administrator is configuring a new service registration using the HTTP API. The service must be discoverable via DNS and must include metadata about its environment and version. Which TWO of the following fields should be included in the service definition to meet these requirements? (Choose two.)
A developer has two versions of the payments service registered in Consul: payments-v1 and payments-v2, both with the tag 'production'. They need to query only the v2 instances using the DNS interface. Which DNS query format should they use?
A service named 'inventory' is registered on three nodes in dc1 with tags 'v1' and 'primary'. An operator wants DNS queries for inventory.service.consul to return only instances that carry both tags, not instances with just one. Which query accomplishes this?
A service is registered with Consul using the HTTP API. The service definition includes a health check with an HTTP endpoint. After registration, the service does not appear in DNS queries for healthy instances. Which command should you use to immediately see the health check status and understand why the service is not being returned?
A platform team runs Consul 1.15 with a single datacenter. They register a new service 'payment-api' using the HTTP API and specify a health check with HTTP endpoint 'http://10.0.1.5:8080/health' and interval '10s'. The service is registered, but the Consul UI shows the service as 'critical'. The check script returns HTTP 200 with a JSON body '{"status":"ok"}'. What is the most likely cause of the critical status?
A DevOps engineer is configuring a Consul service registration for a legacy application that cannot expose an HTTP endpoint. The engineer needs to ensure that the service is automatically deregistered if the node fails. Which two of the following approaches will achieve this? (Choose two.)
A Consul cluster is experiencing intermittent service discovery failures. An operator notices that some service instances are intermittently missing from DNS query results, but they appear as healthy in the Consul UI. Which configuration parameter should be adjusted to ensure consistent DNS results?
A service 'database' is registered with Consul and has a health check that is currently in the 'warning' state. A client queries the DNS interface for 'database.service.consul'. What will be the result?
A service named 'auth' is registered with a health check that is currently critical. A developer queries auth.service.consul via DNS and receives no healthy endpoints. Which Consul behavior explains why the unhealthy instance is excluded from DNS results?
A developer needs to discover the 'catalog' service using the Consul DNS interface. The service is registered with the tag 'v2'. Which two DNS query formats correctly return only instances tagged 'v2'? (Choose two.)
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 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'?
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 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?
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?
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 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?
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?
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?
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 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?
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?
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?
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 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?
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.)
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?
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?
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?
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?