Skip to main content or flannel?

Weave offers a number of projects all related and meant to integrate nicely. The basic service is intra and extra spanning private networks between Docker containers in node(s). This article indicates that rkt is also supported. Weave's killer feature is their scope app which is a container visualization and portal. (as portals go the tool bypasses all authentication and that might not be a good thing) One missing feature here is that weave's DNS is not available to the node; only the containers.

Flannel implements a similar network model, however, there is no DNS and there is no visualization unless the later is part of their paid offering. I've had a lot of good luck with flannel and the one thing I like is that it looks and feels a lot like CoreOS' other tools and so administration feels consistent.

While Flannel is experimenting on multiple networks it is experimental and not working in the most useful edge cases.

problem 1:
Container network and DNS design is no different than previous virtual guest OS' and domain 0 hosts. Weave's DNS seems limited to the containers and not the node.

problem 2:
Weave does not mention multi networking at all

problem 3:
scope bypasses security

problem 4:
rebooting/restarting weave can severely cripple requiring a full service restart

One solution I like is using skyDNS when containers register. The challenge here is naming container properly so they cooperate. Installing an haproxy instance on every node probably does not require a general purpose hostname unless I'm deploying some sort of round robin strategy and in that case the DNS records would be different. Still a better solution.

Popular posts from this blog

Prometheus vs Bosun

In conclusion... while Bosun(B) is still not the ideal monitoring system neither is Prometheus(P).


I am running Bosun in a Docker container hosted on CoreOS. Fleet service/unit files keep it running. However in once case I have experienced at least one severe crash as a result of a disk full condition. That it is implemented as part golang, java and python is an annoyance. The MIT license is about the only good thing.

I am trying to integrate Prometheus into my pipeline but losing steam fast. The Prometheus design seems to desire that you integrate your own cache inside your application and then allow the server to scrape the data, however, if the interval between scrapes is shorter than the longest transient session of your application then you need a gateway. A place to shuttle your data that will be a little more persistent.

(1) storing the data in my application might get me started more quickly
(2) getting the server to pull the data might be more secure
(3) using a push g…

Entry level cost for CoreOS+Tectonic

CoreOS and Tectonic start their pricing at 10 servers. Managed CoreOS starts at $1000 per month for those first 10 servers and Tectonic is $5000 for the same 10 servers. Annualized that is $85K or at least one employee depending on your market. As a single employee company I'd rather hire the employee. Specially since I only have 3 servers.

The pricing is biased toward the largest servers with the largest capacities; my dual core 32GB i5 IntelNuc can never be mistaken for a 96-CPU dual or quad core DELL

If CoreOS does not figure out a different barrier of entry they are going to follow the Borland path to obscurity.

Weave vs Flannel

While Weave and Flannel have some features in common weave includes DNS for service discovery and a wrapper process for capturing that info. In order to get some parity you'd need to add a DNS service like SkyDNS and then write your own script to weave the two together.
In Weave your fleet file might have some of this:
[Service] . . . ExecStartPre=/opt/bin/weave run --net=host --name bob ncx/bob ExecStart=/usr/bin/docker attach bob
In sky + flannel it might look like:
[Service] . . . ExecStartPre=docker run -d --net=host --name bob ncx/bob ExecStartPre=etcdctl set /skydns/local/ncx/bob '{"host":"`docker inspect --format '{{ .NetworkSettings.IPAddress }}' bob`","port":8080}' ExecStart=/usr/bin/docker attach bob
I'd like it to look like this:
[Service] . . . ExecStartPre=skyrun --net=host --name bob ncx/bob ExecStart=/usr/bin/docker attach bob
That's the intent anyway. I'm not sure the exact commands will work and that's partly why we…