Cloud Foundry application deployment fails due to EHOSTUNREACH error

Cloud Foundry application deployment fails due to EHOSTUNREACH error.

Symptoms

When you deploy a Cloud Foundry application, an error similar to the following message is displayed:

-----> Building dependencies
       Installing node modules (package.json)
       npm ERR! Linux 4.4.0-75-generic
       npm ERR! argv "/tmp/app/vendor/node/bin/node" "/tmp/app/vendor/node/bin/npm" "install" "--unsafe-perm" "--userconfig" "/tmp/app/.npmrc"
       npm ERR! node v6.12.2
       npm ERR! npm  v3.10.10
       npm ERR! code EHOSTUNREACH
       npm ERR! errno EHOSTUNREACH
       npm ERR! syscall connect

       npm ERR! connect EHOSTUNREACH 151.101.40.162:443
       npm ERR!
       npm ERR! If you need help, you may report this error at:
       npm ERR!     <https://github.com/npm/npm/issues>

       npm ERR! Please include the following file with any support request:
       npm ERR!     /tmp/app/npm-debug.log
-----> Build failed
       Some possible problems:

       - Node version not specified in package.json
       http://docs.cloudfoundry.org/buildpacks/node/node-tips.html

Failed to compile droplet
Exit status 223
Staging failed: Exited with status 223
Destroying container
Successfully destroyed container

FAILED
Error restarting application: BuildpackCompileFailed

In this message, the failed application or buildpack that is used by the application is trying to access the Internet to download content. If you require the use of an HTTP proxy to reach the Internet, you must configure your application to use the proxy.

Resolving the problem

Log in to Cloud Foundry:
```
cf login
```
Change to the organization and space where the application is deployed:
```
cf target -o <org> -s <space>
```
Set the HTTP proxy variables for the application. For example, if your proxy is http://myproxy.com:3128, run the following command:
```
cf set-env myApp https_proxy "http://myproxy.com:3128"
cf set-env myApp http_proxy "http://myproxy.com:3128"
```
Restart the application. Run the following command:
```
cf restart myApp
```