monder / rkt-sidekick

An aci that writes container ip address to etcd

rkt-sidekick

An ACI that writes container ip address to etcd. That provides the more rkt-like approach to sidekick model implementation which comes in handy when using multihost network solutions such as flannel

Images

Signed ACIs for linux-arm64 are available at monder.cc/rkt-sidekick with versions matching git tags.

Usage

rkt run \
   --insecure-options=image \
   --net=flannel \
   docker://redis \
   monder.cc/rkt-sidekick:v0.1.0 -- -cidr 10.0.0.0/16 -format '{"host":"$ip", "port":3000}' /services/redis-a6f43b/ip

The script above will launch redis and a sidekick in the same pod. The sidekick will enumerate all network interfaces and write the first one matching 10.0.0.0/16 to the formatted string to /services/redis-a6f43b/ip

Please note how to pass arguments to multiple images: https://coreos.com/rkt/docs/latest/subcommands/run.html#passing-arguments

Other options

Usage: rkt-sidekick route53 [options] [ZONE_ID] [HOSTNAME]

Options:
    -cidr              cidr to match the ip (default: "0.0.0.0/0")  


Usage: rkt-sidekick etcd [options] [KEY_IN_ETCD]

Options:
    -cidr              cidr to match the ip (default: "0.0.0.0/0")
    -etcd-endpoint     an etcd address in the cluster (default: "http://172.16.28.1:2379")
    -format            format of the etcd key value. '$ip' will be replace by container's ip address (default: "$ip")
    -expire-dir        set expiration TTLs for all items under that directory, not only the leaf node
    -interval          refresh interval (default: "1m")

License

MIT

rkt-sidekick's Issues

flannel and etcd setup

would you please describe your flannel and etcd setup. Running etcd on the host and not within the flannel subnet is throwing errors.

optional format string

The user provides a etcd key and the sidekick stores the IP address in that location, however, skyDNS uses a JSON formatted value that include a TTL. It would be helpful if the RUN command could include the format of the value in the go template format or at least Printf() format string.

what is the IP used in DNS when the container spans multiple networks?

In one of my experiments to understand and test this project I had set --net=container,default and the DNS server had the wrong IP address.