OCI Networking: Intermittent Connection Timeouts When Accessing Private Subnet Resources from Public Subnet
I keep running into I'm testing a new approach and I'm working on a personal project and I've looked through the documentation and I'm still confused about I've searched everywhere and can't find a clear answer. I'm working with intermittent connection timeouts when my application, hosted on an OCI compute instance in a public subnet, tries to access a database hosted in a private subnet. I'm using Java with the Spring framework, and the database is an Oracle Autonomous Database. The behavior message I receive is `java.sql.SQLRecoverableException: IO behavior: The Network Adapter could not establish the connection`. I've checked the following configurations: 1. The security list associated with the private subnet allows inbound traffic on the database port (1522). 2. The route table for the public subnet has a route to the private subnet. 3. Network security groups (NSG) are configured to allow traffic between the public and private subnet. Here's a snippet of how I'm establishing the connection in my Java application: ```java String jdbcUrl = "jdbc:oracle:thin:@//<private-db-ip>:1522/<database-name>"; Connection connection = DriverManager.getConnection(jdbcUrl, "<username>", "<password>"); ``` The connection works most of the time, but every few minutes, it fails with the aforementioned behavior. I’ve implemented exponential backoff for retries, but that doesn't solve the underlying scenario. I've also verified that the database is up and running during the timeout events. Any insights on what could be causing these intermittent timeouts? Are there specific OCI settings or best practices I might be overlooking that relate to networking between public and private subnets? What's the best practice here? My development environment is Linux. Has anyone else encountered this? I'm working in a CentOS environment. What am I doing wrong?