Bug#698802: release-notes: NSCA compatibility problems should be described

[Hilko Bengen <bengen@debian.org>]

Package: release-notes
Severity: wishlist
Tags: patch

There are a few issues with upgrading from nsca 2.7 to 2.9 that IMO
should be documented in the release notes:

- #670373: nsca 2.7.2 / nsca-client 2.9.1: do not communicate
- #662642: Daemon fails to handle packets with more than five reports
- #685457: nsca: Incompatibility between munin and nsca-2.9.1

Here's a suggestion:

"

Both the command line interface to nsca-client and the network protocol
spoken between nsca-client and nsca have been changed from version
2.7.2+nmu2 (squeeze) to version 2.9.1-2 (wheezy) in incompatible ways:

- nsca 2.7.2 (server) is not able to receive messages from
  nsca-client 2.9.1-2 at all.

- Whereas nsca-client 2.7.2 expected multiple status messages passed to
  it via STDIN to be separated by newline (0x0a) characters, the record
  separator has been changed to a ETB / (0x17) character by 2.9.1.

- It is impossible to transmit more than five status messages during one
  network connection.

To keep a working monitoring setup from breaking over these
incompatibilities, the following steps should be taken before any
systems are upgraded to wheezy:

- All nsca servers should be upgraded to 2.9.1 before any clients are
  upgraded. Squeeze backports of the nsca and nsca-client packages are
  available via backports.debian.org to ease the transition.

- Care should be taken that external programs feeding multiple service
  status records through nsca-client are adapted to use the ETB
  character as a record separator.

  A wrapper script that calls » tr '\n' '\027' « should be sufficient.

  Affected packages are: munin [ FIXME: insert others here ].

- Care should be taken that external programs transmit no more than five
  status records per nsca-client invocation.

"

-- System Information:
Debian Release: 7.0
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.2.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash