Why would OpenStack instances fail to wget a URL and work perfectly on others ? For instance:
$ wget -O - 'https://ceph.com/git/?p=ceph.git;a=blob_plain;f=keys/autobuild.asc' Connecting to ceph.com (ceph.com)|22.214.171.124|:443... connected. HTTP request sent, awaiting response... 200 OK Length: unspecified [text/plain] Saving to: `STDOUT' [< => ] 0 --.-K/s ^
If it can be fixed by lowering the MTU from the default of 1500 to 1400 with:
$ sudo ip link set mtu 1400 dev eth0 $ sudo ip link show dev eth0 2: eth0:
mtu 1400 qdisc pfifo_fast state UP qlen 1000 link/ether fa:16:3e:85:ee:a5 brd ff:ff:ff:ff:ff:ff
it means the underlying OpenStack DHCP should be fixed to set the MTU to 1400.
Continue reading “wget on an OpenStack instance hangs ? Try lowering the MTU”