If you’re experiencing issues with your RDS Proxy being stuck in an “UNAVAILABLE” state due to “PENDING_PROXY_CAPACITY,” here’s a step-by-step guide to help you troubleshoot and resolve the problem.
First, ensure that your network setup is correct. Verify that your security groups allow traffic between the proxy and your database instance. Remember, just sharing a security group between the proxy and database isn’t enough; you need to explicitly allow traffic on port 3306. Add an ingress rule to the security group that permits communication with itself on this port. Confirm that the rule is correctly applied.
Next, check the status of your database instance. It should be marked as “available,” and your engine version must be compatible—here, MySQL 8.0.46. Also, confirm that your credentials in Secrets Manager match the current master username and password of your database.
Then, review the subnet capacity. Each subnet should have more than 4,000 free IP addresses to rule out capacity issues related to IP exhaustion. Also, examine the proxy’s logs and AWS CloudTrail for any errors or events that might shed light on what’s happening.
One common step to clear internal errors is to deregister the target from the proxy and then register it again. This sometimes prompts the control plane to refresh and resolve temporary stuck states. After re-registering, monitor the target’s health. If it remains stuck at “PENDING_PROXY_CAPACITY” with no further ENI creation, the issue might be in how the proxy is scaling.
It’s important to note that capacity scale-up issues sometimes get stuck after a single ENI creation, with no additional progress. If you encounter this, a full delete and recreation of the proxy and target group may be your most reliable solution. However, some users have reported success in unblocking these situations without recreating the entire setup—by retrying deregistration and registration or waiting for the internal processes to resolve naturally.
Finally, keep in mind that if you’ve already checked all configurations—network, security, IAM permissions, and capacity—and the problem persists, it may be an internal issue with RDS Proxy itself. In such cases, reaching out to AWS Support can help escalate the matter and get personalized assistance.
By systematically verifying each aspect and performing targeted actions like deregistering and re-registering your proxy target, you can often resolve these internal capacity issues without drastic measures. If problems continue despite these steps, a full rebuild of your proxy environment might be necessary to restore normal operation.