Hey Mike, let's work through this error together. The ORA-01034: ORACLE not available and ORA-27101: shared memory realm does not exist messages tell us your instant client can't establish a connection to a running Oracle instance. Here's how to troubleshoot and fix this step by step:

Step 1: Verify the Database Container is Running #

First, check if your InfraDB container is actually up and running:

docker ps

Look for a container named InfraDB with a status of Up. If it's stopped, start it with:

docker start InfraDB

Step 2: Confirm Network Connectivity Between Containers #

Since you're using the SampleNET network, make sure both the database container and your instant client container are attached to it:

1. Check the database container's network association:

   docker inspect InfraDB | grep -A 5 Networks
   

   You should see SampleNET listed under its networks.
2. Test if the client can reach the database container:
   Run the instant client container in interactive bash mode first:

   docker run -it --network=SampleNET --rm store/oracle/database-instantclient:12.2.0.1 bash
   

   Then ping InfraDB to confirm connectivity:

   ping InfraDB
   

   If ping fails, manually attach the database container to the network:

   docker network connect SampleNET InfraDB
   

Step 3: Check if the Oracle Instance is Started #

Even if the container is running, the Oracle instance might not have finished initializing or could be stopped. Enter the InfraDB container to verify:

1. Access the container's shell:

   docker exec -it InfraDB bash
   

2. Log in to SQL*Plus locally as SYSDBA:

   sqlplus / as sysdba
   

3. Check the instance status:

   SELECT status FROM v$instance;
   

   If the status is not OPEN, start the instance (this may take a few minutes):

   STARTUP;
   

Step 4: Validate Your Connection String #

Double-check your connection parameters for accuracy:

• Service name mindshift: Verify it's registered with the Oracle listener. In the InfraDB container, run:

  lsnrctl status
  

  Look for mindshift under the "Services Summary" section. If it's missing, you may need to adjust the database's service_name parameter or listener configuration.
• SYSDBA privileges: Ensure the SYS user has remote SYSDBA access. Run this query locally in SQL*Plus:

  SELECT username, sysdba FROM v$pwfile_users WHERE username = 'SYS';
  

  The sysdba column should show TRUE. If not, recreate the password file with SYSDBA privileges enabled.

Step 5: Check Client-Database Version Compatibility #

Your instant client is version 12.2.0.1. Oracle clients can connect to newer database versions (e.g., 18c, 19c) but may have issues with extremely old or cutting-edge versions. If all other steps fail, confirm your InfraDB database version is compatible with 12.2.0.1.

内容的提问来源于stack exchange，提问作者Mike3355