To install the HAProxy Load Balancer, Cloudera uses an example that uses a single
instance of HAProxy, configured with round robin balancing and TCP mode. This allows for
non-terminating https (https passthrough). The HAProxy service can be configured for High
Availability using keepalived.
You must consult your operating system vendor’s documentation for requirements and
the install guide for configuring HAproxy with keepalived.
To install a HAProxy Load Balancer, you must ssh into the HAProxy host, install, and then configure HAProxy:
sudo su -
yum install haproxy -y
cp /etc/haproxy/haproxy.cfg
/etc/haproxy/haproxy.cfg.bak
cat > /etc/haproxy/haproxy.cfg << EOF
global
log
127.0.0.1 local2
chroot
/var/lib/haproxy
pidfile
/var/run/haproxy.pid
user
haproxy
group
haproxy
daemon
defaults
mode
tcp
log
global
option
tcplog
option
dontlognull
option
redispatch
retries
3
maxconn
5000
timeout connect
5s
timeout client
50s
timeout server
50s
listen stats
bind *:8081
mode http
stats enable
stats refresh 30s
stats uri /stats
monitor-uri /healthz
frontend fe_k8s_80
bind *:80
default_backend be_k8s_80
backend be_k8s_80
balance roundrobin
mode tcp
server ecs-server1.example.com 10.10.0.1:80 check
server ecs-server2.example.com 10.10.0.2:80 check
server ecs-server3.example.com 10.10.0.3:80 check
frontend fe_k8s_443
bind *:443
default_backend be_k8s_443
backend be_k8s_443
balance roundrobin
mode tcp
server ecs-server1.example.com 10.10.0.1:443 check
server ecs-server2.example.com 10.10.0.2:443
check
server ecs-server3.example.com 10.10.0.3:443 check
EOF
systemctl enable haproxy
systemctl restart haproxy
systemctl status haproxy
You can verify that all the hosts are shown from the HAproxy UI. However, at
this point the hosts are not listening to the configured ports.
important
Since you already have an ECS cluster running, you
must alter your DNS wildcard to point to the IP address of the HAProxy
server. You cannot change the Application Domain configured through the
ECS wizard. So you must ensure that you send all ingress traffic to the
HAProxy IP address by making that change in the IP address of your
wildcard DNS Record.
note
Application Domain (app_domain property in Cloudera Manager) maps to your wildcard DNS record (For example, app_domain ecs.example.com maps to your DNS entry *.apps.ecs.example.com)
The resolved IP address must be the host IP (or VIP) of your Load Balancer. For more information, see the Verify DNS Step 5 above.
Load Balancer is now installed.
