pve-network.adoc

   1 Network Configuration
   2 ---------------------
   3 include::attributes.txt[]
   4
   5 {pve} uses a bridged networking model. Each host can have up to 4094
   6 bridges. Bridges are like physical network switches implemented in
   7 software. All VMs can share a single bridge, as if
   8 virtual network cables from each guest were all plugged into the same
   9 switch. But you can also create multiple bridges to separate network
  10 domains.
  11
  12 For connecting VMs to the outside world, bridges are attached to
  13 physical network cards. For further flexibility, you can configure
  14 VLANs (IEEE 802.1q) and network bonding, also known as "link
  15 aggregation". That way it is possible to build complex and flexible
  16 virtual networks.
  17
  18 Debian traditionally uses the `ifup` and `ifdown` commands to
  19 configure the network. The file `/etc/network/interfaces` contains the
  20 whole network setup. Please refer to to manual page (`man interfaces`)
  21 for a complete format description.
  22
  23 NOTE: {pve} does not write changes directly to
  24 `/etc/network/interfaces`. Instead, we write into a temporary file
  25 called `/etc/network/interfaces.new`, and commit those changes when
  26 you reboot the node.
  27
  28 It is worth mentioning that you can directly edit the configuration
  29 file. All {pve} tools tries hard to keep such direct user
  30 modifications. Using the GUI is still preferable, because it
  31 protect you from errors.
  32
  33
  34 Naming Conventions
  35 ~~~~~~~~~~~~~~~~~~
  36
  37 We currently use the following naming conventions for device names:
  38
  39 * Ethernet devices: eth[N], where 0 ≤ N (`eth0`, `eth1`, ...)
  40
  41 * Bridge names: vmbr[N], where 0 ≤ N ≤ 4094 (`vmbr0` - `vmbr4094`)
  42
  43 * Bonds: bond[N], where 0 ≤ N (`bond0`, `bond1`, ...)
  44
  45 * VLANs: Simply add the VLAN number to the device name,
  46   separated by a period (`eth0.50`, `bond1.30`)
  47
  48 This makes it easier to debug networks problems, because the device
  49 names implies the device type.
  50
  51 Default Configuration using a Bridge
  52 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  53
  54 The installation program creates a single bridge named `vmbr0`, which
  55 is connected to the first ethernet card `eth0`. The corresponding
  56 configuration in `/etc/network/interfaces` looks like this:
  57
  58 ----
  59 auto lo
  60 iface lo inet loopback
  61
  62 iface eth0 inet manual
  63
  64 auto vmbr0
  65 iface vmbr0 inet static
  66         address 192.168.10.2
  67         netmask 255.255.255.0
  68         gateway 192.168.10.1
  69         bridge_ports eth0
  70         bridge_stp off
  71         bridge_fd 0
  72 ----
  73
  74 Virtual machines behave as if they were directly connected to the
  75 physical network. The network, in turn, sees each virtual machine as
  76 having its own MAC, even though there is only one network cable
  77 connecting all of these VMs to the network.
  78
  79
  80 Routed Configuration
  81 ~~~~~~~~~~~~~~~~~~~~
  82
  83 Most hosting providers do not support the above setup. For security
  84 reasons, they disable networking as soon as they detect multiple MAC
  85 addresses on a single interface.
  86
  87 TIP: Some providers allows you to register additional MACs on there
  88 management interface. This avoids the problem, but is clumsy to
  89 configure because you need to register a MAC for each of your VMs.
  90
  91 You can avoid the problem by ``routing'' all traffic via a single
  92 interface. This makes sure that all network packets use the same MAC
  93 address.
  94
  95 A common scenario is that you have a public IP (assume `192.168.10.2`
  96 for this example), and an additional IP block for your VMs
  97 (`10.10.10.1/255.255.255.0`). We recommend the following setup for such
  98 situations:
  99
 100 ----
 101 auto lo
 102 iface lo inet loopback
 103
 104 auto eth0
 105 iface eth0 inet static
 106         address  192.168.10.2
 107         netmask  255.255.255.0
 108         gateway  192.168.10.1
 109         post-up echo 1 > /proc/sys/net/ipv4/conf/eth0/proxy_arp
 110
 111
 112 auto vmbr0
 113 iface vmbr0 inet static
 114         address  10.10.10.1
 115         netmask  255.255.255.0
 116         bridge_ports none
 117         bridge_stp off
 118         bridge_fd 0
 119 ----
 120
 121
 122 Masquerading (NAT) with `iptables`
 123 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 124
 125 In some cases you may want to use private IPs behind your Proxmox
 126 host's true IP, and masquerade the traffic using NAT:
 127
 128 ----
 129 auto lo
 130 iface lo inet loopback
 131
 132 auto eth0
 133 #real IP adress
 134 iface eth0 inet static
 135         address  192.168.10.2
 136         netmask  255.255.255.0
 137         gateway  192.168.10.1
 138
 139 auto vmbr0
 140 #private sub network
 141 iface vmbr0 inet static
 142         address  10.10.10.1
 143         netmask  255.255.255.0
 144         bridge_ports none
 145         bridge_stp off
 146         bridge_fd 0
 147
 148         post-up echo 1 > /proc/sys/net/ipv4/ip_forward
 149         post-up   iptables -t nat -A POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE
 150         post-down iptables -t nat -D POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE
 151 ----
 152
 153
 154 Linux Bond
 155 ~~~~~~~~~~
 156
 157 Bonding is a technique for binding multiple NIC's to a single network
 158 device.  It is possible to achieve different goals, like make the
 159 network fault-tolerant, increase the performance or both
 160 together.
 161
 162 There are 7 modes for bonding:
 163
 164 * *Round-robin (balance-rr):* Transmit network packets in sequential
 165 order from the first available network interface (NIC) slave through
 166 the last. This mode provides load balancing and fault tolerance.
 167
 168 * *Active-backup (active-backup):* Only one NIC slave in the bond is
 169 active. A different slave becomes active if, and only if, the active
 170 slave fails. The single logical bonded interface's MAC address is
 171 externally visible on only one NIC (port) to avoid distortion in the
 172 network switch. This mode provides fault tolerance.
 173
 174 * *XOR (balance-xor):* Transmit network packets based on [(source MAC
 175 address XOR'd with destination MAC address) modulo NIC slave
 176 count]. This selects the same NIC slave for each destination MAC
 177 address. This mode provides load balancing and fault tolerance.
 178
 179 * *Broadcast (broadcast):* Transmit network packets on all slave
 180 network interfaces. This mode provides fault tolerance.
 181
 182 * *IEEE 802.3ad Dynamic link aggregation (802.3ad)(LACP):* Creates
 183 aggregation groups that share the same speed and duplex
 184 settings. Utilizes all slave network interfaces in the active
 185 aggregator group according to the 802.3ad specification.
 186
 187 * *Adaptive transmit load balancing (balance-tlb):* Linux bonding
 188 driver mode that does not require any special network-switch
 189 support. The outgoing network packet traffic is distributed according
 190 to the current load (computed relative to the speed) on each network
 191 interface slave. Incoming traffic is received by one currently
 192 designated slave network interface. If this receiving slave fails,
 193 another slave takes over the MAC address of the failed receiving
 194 slave.
 195
 196 * *Adaptive load balancing (balanceIEEE 802.3ad Dynamic link
 197 aggregation (802.3ad)(LACP):-alb):* Includes balance-tlb plus receive
 198 load balancing (rlb) for IPV4 traffic, and does not require any
 199 special network switch support. The receive load balancing is achieved
 200 by ARP negotiation. The bonding driver intercepts the ARP Replies sent
 201 by the local system on their way out and overwrites the source
 202 hardware address with the unique hardware address of one of the NIC
 203 slaves in the single logical bonded interface such that different
 204 network-peers use different MAC addresses for their network packet
 205 traffic.
 206
 207 For the most setups the active-backup are the best choice or if your
 208 switch support LACP "IEEE 802.3ad" this mode should be preferred.
 209
 210 The following bond configuration can be used as distributed/shared
 211 storage network. The benefit would be that you get more speed and the
 212 network will be fault-tolerant.
 213
 214 .Example: Use bond with fixed IP address
 215 ----
 216 auto lo
 217 iface lo inet loopback
 218
 219 iface eth1 inet manual
 220
 221 iface eth2 inet manual
 222
 223 auto bond0
 224 iface bond0 inet static
 225       slaves eth1 eth2
 226       address  192.168.1.2
 227       netmask  255.255.255.0
 228       bond_miimon 100
 229       bond_mode 802.3ad
 230       bond_xmit_hash_policy layer2+3
 231
 232 auto vmbr0
 233 iface vmbr0 inet static
 234         address  10.10.10.2
 235         netmask  255.255.255.0
 236         gateway  10.10.10.1
 237         bridge_ports eth0
 238         bridge_stp off
 239         bridge_fd 0
 240
 241 ----
 242
 243
 244 Another possibility it to use the bond directly as bridge port.
 245 This can be used to make the guest network fault-tolerant.
 246
 247 .Example: Use a bond as bridge port
 248 ----
 249 auto lo
 250 iface lo inet loopback
 251
 252 iface eth1 inet manual
 253
 254 iface eth2 inet manual
 255
 256 auto bond0
 257 iface bond0 inet maunal
 258       slaves eth1 eth2
 259       bond_miimon 100
 260       bond_mode 802.3ad
 261       bond_xmit_hash_policy layer2+3
 262
 263 auto vmbr0
 264 iface vmbr0 inet static
 265         address  10.10.10.2
 266         netmask  255.255.255.0
 267         gateway  10.10.10.1
 268         bridge_ports bond0
 269         bridge_stp off
 270         bridge_fd 0
 271
 272 ----
 273
 274 ////
 275 TODO: explain IPv6 support?
 276 TODO: explan OVS
 277 ////