Configuration¶

Here is an example config file:

addrlist:
        - 172.17.0.2:443
        - 172.17.0.3:443
        - 172.17.0.4:443
filter: True
incoming-proxy:
        host: 0.0.0.0
        port: 4443
        protocol: ssl
        diff-class: "rddr_diff_builtins.RddrHttpDiff"
        enforcing: True
outgoing-proxies:
        1.2.3.4:3036:
                host: 0.0.0.0
                ports:
                        - 3001
                        - 3002
                        - 3003
                diff-class: "rddr_diff_builtins.RddrJsonDiff"
                protocol: ssl
                enforcing: True
        some-hostname:5432:
                host: 192.168.99.1
                ports:
                        - 4001
                        - 4002
                        - 4003
                diff-class: "rddr_diff_builtins.RddrPostgresDiff"
                diff-params: {
                    ...
                }
                protocol: tcp
                enforcing: True
verbosity: "DEBUG"

And here is what each of these options configures:

addrlist

Addresses (host:port) of the N application variants we want to proxy. If you are doing filtering (i.e. filter is True), make sure the addresses of the two instances comprising your filter pair appear first in this list.

filter

Specify whether or not to filter non-deterministic noise. This requires you to deploy two identical application instances. This is known as the filter pair. You must list the filter pair instances as the first two entries in addrlist.

incoming-proxy

Configuration of the single proxy for incoming requests to the N variants

host: The hostname or IP which the proxy will bind to. 0.0.0.0 indicates it will bind to all available hostnames/IPs.
port: The port which the proxy will bind to.
protocol: The transport protocol to use for this proxy. One of tcp, ssl.
diff-class: Python class to import for filtering non-deterministic noise. This class must implement the functions diff_traffic and modify_traffic. RDDR ships with four such classes: rddr_diff_builtins.RddrHttpDiff, rddr_diff_builtins.RddrJsonDiff, rddr_diff_builtins.RddrByteDiff, and rddr_diff_builtins.RddrPostgresDiff,
enforcing: When the N variants’ responses to a request differ (after filtering non-deterministic noise), enforcing determines whether or not the server will forward the merged response to the client. enforcing = True will block the response.

outgoing-proxies

Configure one outgoing proxy per backend service that the N variants make requests to.

<dest 1>

This proxy will forward traffic to this destination. Specify the destination as in addrlist: host:port

host: The hostname or IP which the proxy will bind to. 0.0.0.0 indicates it will bind to all available hostnames/IPs.
ports: The list of ports which the proxy will bind to. Each port should accept connections from one of the N instances. The first port in the list corresponds to the first instance in addrlist, the second port with the second instance, and so on. Update the N variants to send their requests to the bound host and the port associated with them. Proxy will bind to <host>:<port_1>, …, <host>:<port_N>.
protocol: The transport protocol to use for this proxy. One of tcp, ssl.
diff-class: Python class to import for filtering non-deterministic noise.
diff-params: Some RDDR diff plugins accept a set of configuration parameters. The plugin will specify its own schema for this field.
enforcing: If the N variants differ in their outgoing requests (after filtering non-deterministic noise), enforcing determines whether or not the server will forward the merged response to the client. enforcing = True will block the request.

…

verbosity

Verbosity level. One of INFO, DEBUG, WARNING, ERROR.

This RDDR deployment can be visualized as:

Block diagram of the above configuration¶