gem install pg -v '0.17.1' not working for some reason

Question

I'm trying to "bundle" by rails app in AWS EC2 Linux server. I'm getting this error for "pg" gem. Could someone help? Can't find solution.

This gem 'pg' has version of 0.17.1.

Ruby version is ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-linux]

$ gem install pg
Building native extensions.  This could take a while...
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

    current directory: /home/ec2-user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/pg-0.21.0/ext
/home/ec2-user/.rbenv/versions/2.3.1/bin/ruby -r ./siteconf20180105-17661-1wdsn6j.rb extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
    --something something something

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /home/ec2-user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/extensions/x86_64-linux/2.3.0-static/pg-0.21.0/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /home/ec2-user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/pg-0.21.0 for inspection.
Results logged to /home/ec2-user/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/extensions/x86_64-linux/2.3.0-static/pg-0.21.0/gem_make.out

Answer 1

I had some problem same as you when i installed gem 'pg' on centos or ubuntu .

For centos, you can do this:

yum install postgresql-libs
yum install postgresql-devel

Then run gem install pg again.

Answer 2

在 Ubuntu 上，我需要运行：

sudo apt-get install libpq-dev