Chapter 4. Networking

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4.1. DNS configuration details

4.1.1. Linux

  • CodeReady Containers expects NetworkManager to be used to manage networking.
  • NetworkManager is set up to use dnsmasq through the /etc/NetworkManager/conf.d/crc-nm-dnsmasq.conf configuration file.
  • The configuration file for this dnsmasq instance is /etc/NetworkManager/dnsmasq.d/crc.conf:

    • The NetworkManager dnsmasq instance forwards requests for the crc.testing and apps-crc.testing domains to the DNS server. This DNS server is a dnsmasq instance running inside of the virtual machine.

4.1.2. macOS

  • CodeReady Containers creates a /etc/resolver/testing file which instructs macOS to forward all DNS requests for the testing domain to the CodeReady Containers virtual machine.
  • CodeReady Containers also adds an api.crc.testing entry to /etc/hosts pointing at the VM IP address. This is needed by the oc binary. See OpenShift issue #23266 for more information.

4.2. Starting CodeReady Containers behind a proxy


  • To use an existing oc binary on your host machine, export the .testing domain as part of the no_proxy environment variable.
  • No manual settings are required to use the embedded oc binary. For more information on using the embedded oc binary, see Section 3.3.2, “Accessing the OpenShift cluster with oc.


  • To start CodeReady Containers behind a proxy:

    1. Define a proxy using the http_proxy and https_proxy environment variables or using the crc config set command as follows:

      $ crc config set http-proxy<port>
      $ crc config set https-proxy<port>
      $ crc config set no-proxy <comma-separated-no-proxy-entries>

      The crc binary will be able to use the defined proxy once set via environment variables or CodeReady Containers configuration.

  • Proxy-related values set in the configuration for CodeReady Containers have priority over values set via environment variables.
  • SOCKS proxies are not supported by OpenShift Container Platform.
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