Category Archives: HOWTO

ORA-12519: TNS:no appropriate service handler found

The number of database processes that can run in Oracle DB is set to 150 as default which can be viewed from v$resource_limit. select * from v$resource_limit where resource_name = ‘processes’; RESOURCE_NAME CURRENT_UTILIZATION MAX_UTILIZATION INITIAL_ALLOCATION LIMIT_VALUE ————- ——————- ————— —————— … Continue reading

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Accessing Host from Docker Container

Sometime we need to access the services that are running in the host machine to be accessible from the docker container.  e.g. In on of my project, we needed to connect to the oracle db (port 1521) from inside the … Continue reading

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My MongoDB cheatsheet

Few years ago, I was working on one mongoDB project.Its a NoSQL database , easy to learn and its pure JSON based. I learned it myself and had created a cheatsheet for it, so I can easily recall it anytime … Continue reading

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chef attribute : avoiding “undefined method `[]’ for nil:NilClass” error

In chef, when a nested attribute that might not exist/or not crated yet, you can use rescue as a modifier to an if statement. For example, assuming that only some of your nodes have node[‘install_wls’][‘isManaged’]defined: if node[‘install_wls’][‘isManaged’] do the stuff … Continue reading

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chef knife tricks: Add a node in an environment

  Sometime during automation of a large deployment process, we have to bootstrap a node , create environment and add the node in that particular environment on the fly.   Bootstraping : 2. Create environment dynamically from inside the programme:(python … Continue reading

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Chef Recipe: Oracle DB 11gR2 EE silent deploy

Chef provides a lot of flexibility and greater choice for infrastructure automation and I prefer it over others. We should design our recipe in such a way that the our recipes without being modified can be used in any environment … Continue reading

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Docker Supervisord – Way to run multiple Demon process in a container

The docker was released keeping in mind, one daemon  per container which makes the container lightweight. Like suppose for running a web application, one container will serve database, one container will server as web server, one container  will server as  caching … Continue reading

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