From 2f8e105b4b90959429e421455aacc7d87a35ab8e Mon Sep 17 00:00:00 2001 From: Dmitry Tantsur Date: Wed, 2 Mar 2016 11:50:34 +0100 Subject: [PATCH] Recommend using dhcp-sequential-ip in the dnsmasq configuration Introspection naturally happens in large bulks, after which it's inactive. Small pool for DHCP addresses means that we'll have conflicts due to how dnsmasq distributes them by default - using hashing. This option tells dnsmasq to allocate IP addresses sequentially instead to avoid these conflicts. See https://bugzilla.redhat.com/show_bug.cgi?id=1301659 for detailed analysis. The drawback of this option is that long-running clients may switch IP addresses if their lease expires. This is not a concern for short introspection process. This change may obsolete the need in the delay between 2 introspections. Change-Id: Id277f3d31902bee16d3b048dbde5c34af905f0bc --- devstack/plugin.sh | 1 + doc/source/install.rst | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/devstack/plugin.sh b/devstack/plugin.sh index fb68cd63d..f2ab2af9d 100644 --- a/devstack/plugin.sh +++ b/devstack/plugin.sh @@ -224,6 +224,7 @@ interface=$IRONIC_INSPECTOR_INTERFACE bind-interfaces dhcp-range=$IRONIC_INSPECTOR_DHCP_RANGE dhcp-boot=pxelinux.0 +dhcp-sequential-ip EOF } diff --git a/doc/source/install.rst b/doc/source/install.rst index ae92732ef..53dc6919a 100644 --- a/doc/source/install.rst +++ b/doc/source/install.rst @@ -125,6 +125,12 @@ As for PXE boot environment, you'll need: enable-tftp tftp-root={TFTP ROOT, e.g. /tftpboot} dhcp-boot=pxelinux.0 + dhcp-sequential-ip + + .. note:: + ``dhcp-sequential-ip`` is used because otherwise a lot of nodes booting + simultaneously cause conflicts - the same IP address is suggested to + several nodes. * You have to install and configure one of 2 available ramdisks: simple bash-based (see `Using simple ramdisk`_) or more complex based on