From 55ac08ab8567df00a7cd91c1d471cd193a926f28 Mon Sep 17 00:00:00 2001 From: Sam Betts Date: Mon, 18 Dec 2017 15:13:48 +0000 Subject: [PATCH] [devstack] Allow setting TFTP max blocksize Configuring the block size correctly for TFTPd prevents fragmentation of the TFTP UDP packets, which can significantly slow down or even prevent servers from booting correctly with PXE. Change-Id: Ic00bbcfb3137edb58479c019edb3fcdc4ef55d69 --- devstack/lib/ironic | 2 ++ devstack/tools/ironic/templates/tftpd-xinetd.template | 2 +- doc/source/install/configure-pxe.rst | 11 +++++++++++ 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/devstack/lib/ironic b/devstack/lib/ironic index d559f3a36f..b69ad39e89 100644 --- a/devstack/lib/ironic +++ b/devstack/lib/ironic @@ -128,6 +128,7 @@ IRONIC_TEMPLATES_DIR=${IRONIC_TEMPLATES_DIR:-$IRONIC_DEVSTACK_DIR/tools/ironic/t IRONIC_BAREMETAL_BASIC_OPS=$(trueorfalse False IRONIC_BAREMETAL_BASIC_OPS) IRONIC_TFTPBOOT_DIR=${IRONIC_TFTPBOOT_DIR:-$IRONIC_DATA_DIR/tftpboot} IRONIC_TFTPSERVER_IP=${IRONIC_TFTPSERVER_IP:-$HOST_IP} +IRONIC_TFTP_BLOCKSIZE=${IRONIC_TFTP_BLOCKSIZE:-$((PUBLIC_BRIDGE_MTU-50))} IRONIC_VM_COUNT=${IRONIC_VM_COUNT:-1} IRONIC_VM_SPECS_CPU=${IRONIC_VM_SPECS_CPU:-1} IRONIC_VM_SPECS_RAM=${IRONIC_VM_SPECS_RAM:-1280} @@ -2143,6 +2144,7 @@ function configure_tftpd { [ -f /etc/init/tftpd-hpa.conf ] && echo "manual" | sudo tee /etc/init/tftpd-hpa.override sudo cp $IRONIC_TEMPLATES_DIR/tftpd-xinetd.template /etc/xinetd.d/tftp sudo sed -e "s|%TFTPBOOT_DIR%|$IRONIC_TFTPBOOT_DIR|g" -i /etc/xinetd.d/tftp + sudo sed -e "s|%MAX_BLOCKSIZE%|$IRONIC_TFTP_BLOCKSIZE|g" -i /etc/xinetd.d/tftp # setup tftp file mapping to satisfy requests at the root (booting) and # /tftpboot/ sub-dir (as per deploy-ironic elements) diff --git a/devstack/tools/ironic/templates/tftpd-xinetd.template b/devstack/tools/ironic/templates/tftpd-xinetd.template index 5f3d03f3bb..ec84b0588f 100644 --- a/devstack/tools/ironic/templates/tftpd-xinetd.template +++ b/devstack/tools/ironic/templates/tftpd-xinetd.template @@ -6,7 +6,7 @@ service tftp wait = yes user = root server = /usr/sbin/in.tftpd - server_args = -v -v -v -v -v --map-file %TFTPBOOT_DIR%/map-file %TFTPBOOT_DIR% + server_args = -v -v -v -v -v --blocksize %MAX_BLOCKSIZE% --map-file %TFTPBOOT_DIR%/map-file %TFTPBOOT_DIR% disable = no # This is a workaround for Fedora, where TFTP will listen only on # IPv6 endpoint, if IPv4 flag is not used. diff --git a/doc/source/install/configure-pxe.rst b/doc/source/install/configure-pxe.rst index 0a14c1eae3..659500722e 100644 --- a/doc/source/install/configure-pxe.rst +++ b/doc/source/install/configure-pxe.rst @@ -63,6 +63,17 @@ node(s) where ``ironic-conductor`` is running. sudo systemctl restart xinetd +.. note:: + + In certain environments the network's MTU may cause TFTP UDP packets to get + fragmented. Certain PXE firmwares struggle to reconstruct the fragmented + packets which can cause significant slow down or even prevent the server from + PXE booting. In order to avoid this, TFTPd provides an option to limit the + packet size so that it they do not get fragmented. To set this additional + option in the server_args above:: + + --blocksize + #. Copy the PXE image to ``/tftpboot``. The PXE image might be found at [1]_: Ubuntu (Up to and including 14.04)::