You can use HAProxy to set up an HTTP proxy in front of the DC/OS Admin Router. For example, this can be useful if you want to present a custom server certificate to user agents connecting to the cluster via HTTPS. DC/OS does not support adding a custom external certificate directly into Admin Router, although it is possible to provide a custom CA certificate as the DC/OS CA.
The HTTP Proxy must perform on-the-fly HTTP request and response header modification, because DC/OS is not aware of the custom hostname and port that is being used by user agents to address the HTTP proxy.
The following instructions provide a tested HAProxy configuration example that handles the named request/response rewriting. This example ensures that the communication between HAProxy and DC/OS Admin Router is TLS-encrypted.
Install HAProxy 1.6.9.
Create an HAProxy configuration for DC/OS. This example is for a DC/OS cluster on AWS. For more information on HAProxy configuration parameters, see the documentation.
You can find your task IP by using the agent IP address DNS entry.
taskname: The name of the task.
framework_name: The name of the framework, if you are unsure, it is likely
global daemon log 127.0.0.1 local0 log 127.0.0.1 local1 notice maxconn 20000 pidfile /var/run/haproxy.pid defaults log global option dontlog-normal mode http retries 3 maxconn 20000 timeout connect 5000 timeout client 50000 timeout server 50000 frontend http # Bind on port 9090. HAProxy will listen on port 9090 on each # available network for new HTTP connections. bind 0.0.0.0:9090 # Specify your own server certificate chain and associated private key. # See https://cbonte.github.io/haproxy-dconv/configuration-1.6.html#5.1-crt # bind *:9091 ssl crt /path/to/browser-trusted.crt # # Name of backend configuration for DC/OS. default_backend dcos # Store request Host header temporarily in transaction scope # so that its value is accessible during response processing. # Note: RFC 7230 requires clients to send the Host header and # specifies it to contain both, host and port information. http-request set-var(txn.request_host_header) req.hdr(Host) # Overwrite Host header to 'dcoshost'. This makes the Location # header in DC/OS Admin Router upstream responses contain a # predictable hostname (NGINX uses this header value when # constructing absolute redirect URLs). That value is used # in the response Location header rewrite logic (see regular # expression-based rewrite in the backend section below). http-request set-header Host dcoshost backend dcos # Option 1: use TLS-encrypted communication with DC/OS Admin Router and # perform server certificate verification (including hostname verification). # If you are using the community-supported version of DC/OS, you must # configure Admin Router with a custom TLS server certificate, see # /mesosphere/dcos/2.0/administering-clusters/. This step # is not required for DC/OS Enterprise. # # Explanation for the parameters in the following `server` definition line: # # 18.104.22.168:443 # # IP address and port that HAProxy uses to connect to DC/OS Admin # Router. This needs to be adjusted to your setup. # # # ssl verify required # # Instruct HAProxy to use TLS, and to error out if server certificate # verification fails. # # ca-file dcos-ca.crt # # The local file `dcos-ca.crt` is expected to contain the CA certificate # that Admin Router's certificate will be verified against. It must be # retrieved out-of-band (on Mesosphere DC/OS Enterprise this can be # obtained via https://dcoshost/ca/dcos-ca.crt) # # verifyhost frontend-xxx.eu-central-1.elb.amazonaws.com # # When verifying the TLS certificate presented by DC/OS Admin Router, # perform hostname verification using the hostname specified here # (expect the server certificate to contain a DNSName SAN that is # equivalent to the hostname defined here). The hostname shown here is # just an example and needs to be adjusted to your setup. server dcos-1 22.214.171.124:443 ssl verify required ca-file dcos-ca.crt verifyhost frontend-xxx.eu-central-1.elb.amazonaws.com # Option 2: use TLS-encrypted communication with DC/OS Admin Router, but do # not perform server certificate verification (warning: this is insecure, and # we hope that you know what you are doing). # server dcos-1 126.96.36.199:443 ssl verify none # # Rewrite response Location header if it contains an absolute URL # pointing to the 'dcoshost' host: replace 'dcoshost' with original # request Host header (containing hostname and port). http-response replace-header Location https?://dcoshost((/.*)?) "http://%[var(txn.request_host_header)]\1"
Start HAProxy with these settings.