At BroCon several people pointed out a need to install Bro packages on
machines that do not have a direct external connection. One idea would
be some kind of proxy scheme where an intermediary git repository
mirrors packages locally; bro-pkg would then pull from there. However,
I don't think any of us really liked that idea much. After a few
rounds of discussions, Seth and I came up with a different idea that
seems easier to manage: extending bro-pkg to bundle packages into
deployment files that can be easily pushed to Bro systems simply by
copying them over.
I’ve tried to flesh this out a bit more, and would be interested to
hear what you all think about this approach. And @Jon: Do you think
this would be doable that way?
Here’s the idea:
1. Generally, one first uses bro-pkg as usual to install packages onto
a local Bro system that does have external Internet connectivity
(this could be just a dummy Bro installation). One installs new
packages there, updates existing ones, etc., until reaching a state
that one wants to push out to the actual Bro system.
2. We add a new “bundle” command to bro-pkg that serializes the
current state of packages into a single file on disk, a “package
bundle”. The bundle contains the complete content of all currently
installed packages, using some kind of suitable container format
(could be just a ZIP file, or whatever works; the internal
representation doesn’t really matter).
3. Users create such a bundle on the local system and then simply copy
that bundle file over to all target Bro machines that do not have a
external connectivity themselves, using whatever mechanism they
have available (e.g., just scp; or maybe through some configuration
management system like Ansible etc.).
4. On the target machine, one runs a corresponding “bro-pkg unbundle”
command on that bundle file. That command will completely replace
the system’s current set of packages with the bundle’s content. As
a result, that machine will now have exactly the same packages
installed as the original system.
This would be the general scheme. A couple of people I talked to at
BroCon confirmed that this would offer a viable solution for them, and
that they would indeed much prefer copying files around over
maintaining local git mirrors.
Some additional thoughts on variations/extensions of this basic scheme:
- I’m not quite sure if the bundle should contain just the packages
themselves or further bro-pkg state as well, such as which packages
are currently loaded. Right now I’m learning towards saying “just
the packages”; that would basically treat bundles just as a
transport mechanism to get packages over to another box. The actual
Bro machines would still keep control over which packages to
actually load, etc.
- As it is described above, Step 1 would require having a local Bro
installation into which packages get installed before they can be
bundled up. It would be nice to have a mode where bro-pkg can
operate without having a Bro around at all, just downloading
packages locally somewhere for bundling them up. I could also see
offering an even simpler mode where one simply lists packages to
bundle on the command-line: “bro-pkg bundle <pkg1> <pkg2> <pkg3>”.
That would be particularly useful with configuration management
systems I think.
- It would be neat if bro-pkg's Python library exposed operations to
inspect & retrieve the content of a bundle, such as iterating over
the packages inside a bundle and iterating over the files inside a
package. That way one could easily build target-side scripts that
process and validate bundles before going ahead and installing them
(e.g., imposing custom restrictions on what kind of packages one
allows to put in place; or ensuring that a bundle always contains a
set of packages the site deems mandatory, to avoid configuration
mistakes; or even just logging what gets pushed out).
What do you guys think about this?
Robin