| 1 | [[PageOutline]] |
| 2 | |
| 3 | = Configuring dataplane interfaces on MyPLC PlanetLab nodes = |
| 4 | |
| 5 | This page discusses how to configure secondary interfaces on MyPLC-controlled PlanetLab nodes. |
| 6 | |
| 7 | == Interface numbering gotchas == |
| 8 | |
| 9 | PlanetLab nodes boot using a two-stage process. When multiple interface cards are present, the first-stage boot and second-stage boot may not number the interfaces consistently. This typically causes the node to be unusable. |
| 10 | |
| 11 | We don't know how to control which interface the first-stage boot will use as eth0. However, it is easy to use the MyPLC interface to control which MAC address should be assigned as each interface in the second-stage boot. This section describes how we force MyPLC to use the same interface allocation in second-stage boot as it did in first-stage, allowing the node to be used even if these settings do not natively match. |
| 12 | |
| 13 | === Step 1: Boot into first-stage with the control interface connected === |
| 14 | |
| 15 | Before booting the node, physically connect the control interface cable to the interface which first-stage boot will choose as `eth0`. On our lab nodes (1U Dell R300s), first-stage boot always chooses the leftmost interface on the leftmost expansion NIC to be `eth0` (or the leftmost interface on the motherboard if there are no expansion cards). In your environment, you may need to find this interface by guesswork: if the node can successfully enter first-stage boot and seems to reach a server, you guessed right. |
| 16 | |
| 17 | === Step 2: Use the first-stage boot logs to identify the MAC address of eth0 === |
| 18 | |
| 19 | The MyPLC gathers logs from each node's first-stage boot. These logs will contain the MAC address of first-stage `eth0` on your node. To find this, login to MyPLC, and do: |
| 20 | {{{ |
| 21 | sudo find /var/log/bm/raw | grep <node_hostname> | sort | tail -1 | xargs sudo grep macs |
| 22 | }}} |
| 23 | That command should report output similar to this: |
| 24 | {{{ |
| 25 | $ sudo find /var/log/bm/raw | grep <node_hostname> | sort | tail -1 | xargs sudo grep macs |
| 26 | 19:48:22(UTC) net:InitInterfaces macs = {'00:00:00:00:00:00': 'lo', 'aa:bb:cc:dd:ee:ff': 'eth0'} |
| 27 | }}} |
| 28 | |
| 29 | Use the reported MAC address: |
| 30 | * `<eth0_mac>`: `aa:bb:cc:dd:ee:ff` |
| 31 | |
| 32 | === Step 3: Configure MyPLC to use the correct MAC in stage 2 === |
| 33 | |
| 34 | Use the PlanetLab UI to force the second-stage boot to use the leftmost interface on the leftmost expansion card: |
| 35 | * Browse to the MyPLC web interface and login as an administrator |
| 36 | * Click "My Site Nodes" in the left menubar |
| 37 | * Click "`<node_hostname>`" in the table of nodes |
| 38 | * Expand the "One interface" menu |
| 39 | * Click the IP of the primary interface |
| 40 | * Set MAC to `<eth0_mac>` |
| 41 | * Click "Update" |
| 42 | * Click "Back to Node" |
| 43 | * Click "Update Node" |
| 44 | * Reboot the node |
| 45 | |
| 46 | === Step 4: Modify udev to fix the live interface configuration === |
| 47 | |
| 48 | Sometimes, Fedora gets confused by eth0 switching identities, as a result of which eth1 or eth2 (if you have that many interfaces) does not appear, and is replaced by a weird `devNNNNN` interface. This appears to be fixable by modifying udev's configuration: |
| 49 | |
| 50 | * Login to the node as root |
| 51 | * Edit `/etc/udev/rules.d/70-persistent-net.rules` |
| 52 | * Find a configuration section containing the comment `(custom name provided by external tool)`, e.g.: |
| 53 | {{{ |
| 54 | # PCI device 0x8086:0x10c9 (igb) (custom name provided by external tool) |
| 55 | SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:1b:21:4b:3f:ac", ATTR{type}=="1", NAME="eth0" |
| 56 | }}} |
| 57 | Make sure that there is only one such section, and that its MAC address matches `<eth0_mac>` |
| 58 | * Delete all SUBSYSTEM comment-and-line blocks except this one, and save the file |
| 59 | * Reboot the node |
| 60 | |