使用 Java 修改 AWS 文件？

Question

I would like to build a centOS 7 instance on AWS and install Apache to build web server. After that, I would like to modify the config file, /etc/hosts and /etc/httpd/conf.d/test.conf where test.conf is created by me.

Can I use java to modify the file directly? Or I should create the file and replace the old file on instance? I am little bit confused for the feasibility. Please someone help.

Answer 1

There seem to be a few questions here, so I've split them out.

Q: Can I use programming language X to modify a file on the local filesystem?
A: Yes, with very few exceptions. For Java, yes (if the instance has a JRE).

Q: Should I use Java?
A: Probably not the first choice (you could probably do what you need in a shell script at launch).

Q: Should I create the Apache config files dynamically or build them into an AMI ?
A: Difficult to answer without more information. There are pros and cons to AMIs. If it's simple and quick to create/modify the files on launch, then I'd do it that way.

DevOps is a big subject and there are many options available to you for bootstrapping EC2 instances. Pre-baked AMIs is one option. Another simple option that you might consider is to write userdata scripts , that run at launch time, and that set up the instance for you (see simple nginx example ). They can install software, modify config files, start services, and other things. They can also pull collateral such as pre-staged config files from S3, which can be a handy option.