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+---
+title: Air Gap Configuration
+weight: 138
+---
+
+In the airgap environment, `Docker Registry`, `RancherOS Reposirotries URL` and `RancherOS Upgrade URL` should be configured to ensure the os can pull images and update os services and upgrade os.
+
+
+### Configuring Private Docker Registry
+
+You should use private docker registry for `user-docker` and `system-docker` to pull images.
+
+1. Add [Images prefix]({{< baseurl >}}/os/v1.x/en/installation/configuration/images-prefix/) for private docker registries.
+2. Set private registries certificates for `user-docker`
+  - [Certificates for private registries]({{< baseurl >}}/os/v1.x/en/installation/configuration/private-registries/#certificates-for-private-registries)
+3. Set private registries certificates for `system-docker`
+  1. To set the private registries certificates before the RancherOS startup, RancherOS provide a way to flush your custom certs to the ISO. See how to [set custom certs to ISO]({{< baseurl >}}/os/v1.x/en/installation/configuration/airgap-configuration/#set-custom-certs-to-iso)
+  2. You can also set the private registries certificates after the RancherOS startup.
+      - Append your private registries certs to `/etc/ssl/certs/ca-certificates.crt.rancher` file then reboot to make the certs fully take effect.
+4. The images used by RancherOS should be pushed to your private registries.
+
+#### Set custom certs to ISO
+
+RancherOS provide a [script](https://github.com/rancher/os/blob/master/scripts/tools/flush_crt_iso.sh) to set your custom certs to a ISO. The following commands show how to use the script to flush certs into a ISO.
+```shell
+$ git clone https://github.com/rancher/os.git
+$ cd os
+$ make shell-bind
+$ cd scripts/tools/
+$ wget http://link/rancheros-xx.iso
+$ wget http://link/custom.crt
+$ ./flush_crt_iso.sh --iso rancheros-xx.iso --cert custom.crt
+$ exit
+
+$ ls ./build/
+```
+
+### Configuring RancherOS Reposirotries and Upgrade URL
+
+By default, RancherOS will update the `engine`, `console`,  `service` list from `https://raw.githubusercontent.com/rancher/os-services` and update `os` list from `https://releases.rancher.com/os/releases.yml`.  
+So in the airgap environment, you should change the Reposirotries URL and Upgrade URL to your own URL.
+
+#### 1. Clone os-services files
+
+Clone `github.com/rancher/os-services` to local. The repo has many branches named after the RancherOS versions. Please checkout the branch that you are using.
+
+```
+$ git clone https://github.com/rancher/os-services.git
+$ cd os-services
+$ git checkout v1.5.2
+```
+
+#### 2. Download the os releases yaml
+
+Download the `releases.yml` from `https://releases.rancher.com/os/releases.yml`.
+
+#### 3. Serve these files by HTTP
+
+Use a HTTP server to serve the cloned `os-services` directory and downloaded `releases.yml`.   
+Make sure you can access all the files in `os-services` and `releases.yml` by URL.
+
+#### 4. Set the URLs to `rancher.repositories.core.url` and `rancher.upgrade.url`.
+
+In your cloud-config, set `rancher.repositories.core.url` and `rancher.upgrade.url` to your own `os-services` URL.
+```yaml
+#cloud-config
+rancher:
+  repositories:
+    core:
+      url: https://foo.bar.com/os-services
+  upgrade:
+    url: https://foo.bar.com/os/releases.yml
+```
+
+You can also customize `rancher.repositories.core.url` and `rancher.upgrade.url` after it's been started using `ros config`.
+
+```
+$ sudo ros config set rancher.repositories.core.url https://foo.bar.com/os-services
+$ sudo ros config set rancher.upgrade.url https://foo.bar.com/os/releases.yml
+```
+
+### Example Cloud-config
+
+Here is an total cloud-config example for using RancherOS in airgap environment.
+For `system-docker`, see [Configuring Private Docker Registry]({{< baseurl >}}/os/v1.x/en/installation/configuration/airgap-configuration/#configuring-private-docker-registry).
+
+```yaml
+#cloud-config
+write_files:
+  - path: /etc/docker/certs.d/myregistrydomain.com:5000/ca.crt
+    permissions: "0644"
+    owner: root
+    content: |
+      -----BEGIN CERTIFICATE-----
+      MIIDJjCCAg4CCQDLCSjwGXM72TANBgkqhkiG9w0BAQUFADBVMQswCQYDVQQGEwJB
+      VTETMBEGA1UECBMKU29tZS1TdGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lkZ2l0
+      cyBQdHkgTHRkMQ4wDAYDVQQDEwVhbGVuYTAeFw0xNTA3MjMwMzUzMDdaFw0xNjA3
+      MjIwMzUzMDdaMFUxCzAJBgNVBAYTAkFVMRMwEQYDVQQIEwpTb21lLVN0YXRlMSEw
+      HwYDVQQKExhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQxDjAMBgNVBAMTBWFsZW5h
+      MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxdVIDGlAySQmighbfNqb
+      TtqetENPXjNNq1JasIjGGZdOsmFvNciroNBgCps/HPJphICQwtHpNeKv4+ZuL0Yg
+      1FECgW7oo6DOET74swUywtq/2IOeik+i+7skmpu1o9uNC+Fo+twpgHnGAaGk8IFm
+      fP5gDgthrWBWlEPTPY1tmPjI2Hepu2hJ28SzdXi1CpjfFYOiWL8cUlvFBdyNqzqT
+      uo6M2QCgSX3E1kXLnipRT6jUh0HokhFK4htAQ3hTBmzcxRkgTVZ/D0hA5lAocMKX
+      EVP1Tlw0y1ext2ppS1NR9Sg46GP4+ATgT1m3ae7rWjQGuBEB6DyDgyxdEAvmAEH4
+      LQIDAQABMA0GCSqGSIb3DQEBBQUAA4IBAQA45V0bnGPhIIkb54Gzjt9jyPJxPVTW
+      mwTCP+0jtfLxAor5tFuCERVs8+cLw1wASfu4vH/yHJ/N/CW92yYmtqoGLuTsywJt
+      u1+amECJaLyq0pZ5EjHqLjeys9yW728IifDxbQDX0cj7bBjYYzzUXp0DB/dtWb/U
+      KdBmT1zYeKWmSxkXDFFSpL/SGKoqx3YLTdcIbgNHwKNMfTgD+wTZ/fvk0CLxye4P
+      n/1ZWdSeZPAgjkha5MTUw3o1hjo/0H0ekI4erZFrZnG2N3lDaqDPR8djR+x7Gv6E
+      vloANkUoc1pvzvxKoz2HIHUKf+xFT50xppx6wsQZ01pNMSNF0qgc1vvH
+      -----END CERTIFICATE-----
+rancher:
+  environment:
+    REGISTRY_DOMAIN: xxxx.yyy
+  repositories:
+    core:
+      url: https://foo.bar.com/os-services
+  upgrade:
+    url: https://foo.bar.com/os/releases.yml
+```