Category: Development

HAProxy in front of Ceph Manager dashboard

The Ceph Mgr dashboard plugin allows for an easy dashboard which can show you how your Ceph cluster is performing.

In certain situations you can’t contact the Mgr daemons directly and you have to place a Proxy server between your computer and the Mgr daemons.

This can be done easily with HAProxy and the following configuration which assumes that:

  • SSL has been disabled in the Dashboard plugin
  • Dashboard plugin listens in port 8080
  • Mgr is running on the hosts mon01, mon02 and mon03
global
  log         127.0.0.1 local1
  log         127.0.0.1 local2 notice

  chroot      /var/lib/haproxy
  pidfile     /var/run/haproxy.pid
  maxconn     4000
  user        haproxy
  group       haproxy
  daemon

  stats socket /var/lib/haproxy/stats

defaults
  log                     global
  mode                    http
  retries                 3
  timeout http-request    10s
  timeout queue           1m
  timeout connect         10s
  timeout client          1m
  timeout server          1m
  timeout http-keep-alive 10s
  timeout check           10s
  maxconn                 3000
  option                  httplog
  no option               httpclose
  no option               http-server-close
  no option               forceclose

  stats enable
  stats hide-version
  stats refresh 30s
  stats show-node
  stats uri /haproxy?stats
  stats auth admin:haproxy

frontend https
  bind *:80
  default_backend ceph-dashboard

backend ceph-dashboard
  balance roundrobin
  option httpchk GET /
  http-check expect status 200
  server mon01 mon01:8080 check
  server mon02 mon02:8080 check
  server mon03 mon03:8080 check

You can now point your browser to the URL/IP of your HAProxy and use your Ceph dashboard.

In case a Mgr machine fails the health checks of HAProxy will make sure it fails over to on of the other Mgr daemons.

Renaming a network interface with systemd-networkd on Ubuntu 18.04

On a Ubuntu system where I’m creating a VXLAN Proof of Concept with CloudStack I wanted to rename the interface enp5s0 to cloudbr0.

I found many documentation on the internet on how to do this with *.link files, but I was missing the golden tip, which was you need to re-generate your initramfs.

/etc/systemd/network/50-cloudbr0.link

[Match]
MACAddress=00:25:90:4b:81:54

[Link]
Name=cloudbr0

After you create this file, re-generate your initramfs:

update-initramfs -c -k all

You can now use cloudbr0 in *.network files to use it like any other network interface.

In my case this is how my interfaces look like:

1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
6: cloudbr0:  mtu 9000 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:25:90:4b:81:54 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.11/24 brd 192.168.0.255 scope global cloudbr0
       valid_lft forever preferred_lft forever
    inet6 2a00:f10:114:0:225:90ff:fe4b:8154/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 2591993sec preferred_lft 604793sec
    inet6 fe80::225:90ff:fe4b:8154/64 scope link 
       valid_lft forever preferred_lft forever
8: cloudbr1:  mtu 1450 qdisc noqueue state UP group default qlen 1000
    link/ether 86:fa:b6:31:6e:c1 brd ff:ff:ff:ff:ff:ff
    inet 172.16.0.11/24 brd 172.16.0.255 scope global cloudbr1
       valid_lft forever preferred_lft forever
    inet6 fe80::84fa:b6ff:fe31:6ec1/64 scope link 
       valid_lft forever preferred_lft forever
9: vxlan100:  mtu 1450 qdisc noqueue master cloudbr1 state UNKNOWN group default qlen 1000
    link/ether 56:df:29:8d:db:83 brd ff:ff:ff:ff:ff:ff

VXLAN with VyOS and Ubuntu 18.04

VXLAN

Virtual Extensible LAN uses encapsulation technique to encapsulate OSI layer 2 Ethernet frames within layer 4 UDP datagrams. More on this can be found on the link provided.

For a Ceph and CloudStack environment I needed to set up a Proof-of-Concept using VXLAN and some refurbished hardware. The main purpose of this PoC is to verify that VXLAN works with CloudStack, Ceph and Ubuntu 18.04

VyOS

VyOS is an open source network operating system based on Debian Linux. It supports VXLAN, so using this we were able to test VXLAN in this setup.

In production a other VXLAN capable router would be used, but for a PoC VyOS works just fine running on a regular server.

Configuration

The VyOS router is connected to ‘the internet’ with one NIC and the other NIC is connected to a switch.

Using static routes a IPv4 subnet (/24) and a IPv6 subnet (/48) are routed towards the VyOS router. These are then splitted and send to multiple VLANs.

As it took me a while to configure VXLAN under VyOS

I’m only posting that configuration.

interfaces {
    ethernet eth0 {
        address 31.25.96.130/30
        address 2a00:f10:100:1d::2/64
        duplex auto
        hw-id 00:25:90:80:ed:fe
        smp-affinity auto
        speed auto
    }
    ethernet eth5 {
        duplex auto
        hw-id a0:36:9f:0d:ab:be
        mtu 9000
        smp-affinity auto
        speed auto
        vif 300 {
            address 192.168.0.1/24
            description VXLAN
            mtu 9000
        }
    vxlan vxlan1000 {
        address 10.0.0.1/23
        address 2a00:f10:114:1000::1/64
        group 239.0.3.232
        ip {
            enable-arp-accept
            enable-arp-announce
        }
        ipv6 {
            dup-addr-detect-transmits 1
            router-advert {
                cur-hop-limit 64
                link-mtu 1500
                managed-flag false
                max-interval 600
                name-server 2a00:f10:ff04:153::53
                name-server 2a00:f10:ff04:253::53
                other-config-flag false
                prefix 2a00:f10:114:1000::/64 {
                    autonomous-flag true
                    on-link-flag true
                    valid-lifetime 2592000
                }
                reachable-time 0
                retrans-timer 0
                send-advert true
            }
        }
        link eth5.300
        mtu 1500
        vni 1000
    }
    vxlan vxlan2000 {
        address 109.72.91.1/26
        address 2a00:f10:114:2000::1/64
        group 239.0.7.208
        ipv6 {
            dup-addr-detect-transmits 1
            router-advert {
                cur-hop-limit 64
                link-mtu 1500
                managed-flag false
                max-interval 600
                name-server 2a00:f10:ff04:153::53
                name-server 2a00:f10:ff04:253::53
                other-config-flag false
                prefix 2a00:f10:114:2000::/64 {
                    autonomous-flag true
                    on-link-flag true
                    valid-lifetime 2592000
                }
                reachable-time 0
                retrans-timer 0
                send-advert true
            }
        }
        link eth5.300
        mtu 1500
        vni 2000
    }
}

VLAN 300 on eth5 is used to route VNI 1000 and 2000 in their own multicast groups.

The MTU of eth5 is set to 9000 so that the encapsulated traffic of VXLAN can still be 1500 bytes.

Ubuntu 18.04

To test if VXLAN was actually working on the Ubuntu 18.04 host I made a very simple script:

ip link add vxlan1000 type vxlan id 1000 dstport 4789 group 239.0.3.232 dev vlan300 ttl 5
ip link set up dev vxlan1000
ip addr add 10.0.0.11/23 dev vxlan1000
ip addr add 2a00:f10:114:1000::101/64 dev vxlan1000

That works! I can ping 10.0.0.11 and 2a00:f10:114:1000::1 from my Ubuntu 18.04 machine!