1.15.3 HA kubernetes Cluster Playbook (load balance)

2020-09-10kubernetes • centos29

Objective

variables

Tip: execute the variables in all console (masters) at the very begining, make sure all servers are using the exact same value (and avoid manual input)

## change if necessary
# hostname
master01Name='master01'
master02Name='master02'
master03Name='master03'
# ipaddress
master01IP='192.168.100.200'
master01IP='192.168.100.201'
master01IP='192.168.100.202'
virtualIP='192.168.100.250'
leadIP="${master01IP}"
leadName="${master01Name}"
k8sVer='v1.15.3'
cfsslDownloadUrl='https://pkg.cfssl.org/R1.2'
etcdVer='v3.3.15'
etcdDownloadUrl='https://github.com/etcd-io/etcd/releases/download'
etcdSSLPath='/etc/etcd/ssl'
etcdInitialCluster="${master01Name}=https://${master01IP}:2380,${master02Name}=https://${master02IP}:2380,${master03Name}=https://${master03IP}:2380"
keepaliveVer='2.0.18'
haproxyVer='2.0.6'
helmVer='v2.14.3'
interface=$(netstat -nr | grep -E 'UG|UGSc' | grep -E '^0.0.0|default' | grep -E '[0-9.]{7,15}' | awk -F' ' '{print $NF}')
ipAddr=$(ip a s "${interface}" | sed -rn 's|\W*inet[^6]\W*([0-9\.]{7,15}).*$|\1|p')
peerName=$(hostname)

keepalived

configuration

Tip: keepalived configuration need to be setup in all kubernetes masters

with haproxy

$ sudo bash -c 'cat > /etc/keepalived/keepalived.conf' << EOF
! Configuration File for keepalived
global_defs {
  router_id LVS_DEVEL
}
vrrp_script check_haproxy {
  script "killall -0 haproxy"
  interval 3
  weight -2
  fall 10
  rise 2
}
vrrp_instance VI_1 {
  state MASTER
  interface ${interface}
  virtual_router_id 51
  priority 50
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 35f18af7190d51c9f7f78f37300a0cbd
  }
  virtual_ipaddress {
    ${virtualIP}
  }
  track_script {
    check_haproxy
  }
}
EOF

without haproxy

keepalived.conf

$ sudo bash -c 'cat > /etc/keepalived/keepalived.conf' << EOF
! Configuration File for keepalived
global_defs {
  router_id LVS_DEVEL
}
vrrp_script check_apiserver {
  script "/etc/keepalived/check_apiserver.sh"
  interval 3
  weight -2
  fall 10
  rise 2
}
vrrp_instance VI_1 {
  state MASTER
  interface ${interface}
  virtual_router_id 51
  priority 50
  authentication {
    auth_type PASS
    auth_pass 4be37dc3b4c90194d1600c483e10ad1d
  }
  virtual_ipaddress {
    ${virtualIP}
  }
  track_script {
    check_apiserver
  }
}
EOF

check_apiserver.sh

$ sudo bash -c 'cat > /etc/keepalived/check_apiserver.sh' << EOF
#!/bin/sh
errorExit() {
  echo "*** \$*" 1>&2
  exit 1
}
curl --silent                           \
     --max-time 2                       \
     --insecure https://localhost:6443/ \
     -o /dev/null                       \
     || errorExit 'Error GET https://localhost:6443/'
if ip addr | grep -q ${virtualIP}; then
  curl --silent                                  \
       --max-time 2                              \
       --insecure https://${virtualIP}:6443/     \
       -o /dev/null                              \
       || errorExit "Error GET https://${virtualIP}:6443/"
fi
EOF

enable keepalived services in all masters

start keepalived serice and verify

$ sudo systemctl enable keepalived.service
$ sudo systemctl start keepalived.service

Tip: One of the master will be setup to virutal dual networking card and show 2 ip addresses.
The one without Broadcast is the virutal IP.

verify

$ sudo systemctl is-enabled keepalived.service
enabled
$ sudo systemctl is-active keepalived.service
active
$ ip -4 a s ${interface}
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:50:50:85:96:64 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.202/24 brd 192.168.100.255 scope global noprefixroute eno1
       valid_lft forever preferred_lft forever
    inet 192.168.100.250/32 scope global eno1
       valid_lft forever preferred_lft forever

click for more details

$ for i in {1..3}; do
  -> echo '---------'
  -> ssh -q devops@master0${i} "/usr/sbin/ip -4 a s $(netstat -nr | grep -E 'UG|UGSc' | grep -E '^0.0.0|default' | grep -E '[0-9.]{7,15}' | awk -F' ' '{print $NF}')"
  -> done
---------
2: eno1:  mtu 1500 qdisc mq state UP group default qlen 1000
    inet 192.168.100.200/24 brd 192.168.100.255 scope global noprefixroute eno1
       valid_lft forever preferred_lft forever
---------
2: eno1:  mtu 1500 qdisc mq state UP group default qlen 1000
    inet 192.168.100.201/24 brd 192.168.100.255 scope global noprefixroute eno1
       valid_lft forever preferred_lft forever
---------
2: eno1:  mtu 1500 qdisc mq state UP group default qlen 1000
    inet 192.168.100.202/24 brd 192.168.100.255 scope global noprefixroute eno1
       valid_lft forever preferred_lft forever
    inet 192.168.100.250/32 scope global eno1       <<<< virtual ip in master node 03
       valid_lft forever preferred_lft forever

$ for i in {1..3}; do
  -> ssh -q devops@master0${i} "sudo systemctl status keepalived"
  -> echo ''
  -> done
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/etc/systemd/system/keepalived.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2019-09-03 01:13:17 PDT; 18min ago
  Process: 26437 ExecStart=/usr/local/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 26438 (keepalived)
    Tasks: 2
   Memory: 652.0K
   CGroup: /system.slice/keepalived.service
           ├─26438 /usr/local/sbin/keepalived -D
           └─26439 /usr/local/sbin/keepalived -D
Sep 03 01:15:35 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:36 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:37 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:38 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:39 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:40 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:41 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:42 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:43 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
Sep 03 01:15:43 master01 Keepalived_vrrp[26439]: (VI_1) ip address associated with VRID 51 not present in MASTER advert : 10.69.78.50
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/etc/systemd/system/keepalived.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2019-09-03 01:17:24 PDT; 14min ago
  Process: 32672 ExecStart=/usr/local/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 32673 (keepalived)
    Tasks: 2
   Memory: 652.0K
   CGroup: /system.slice/keepalived.service
           ├─32673 /usr/local/sbin/keepalived -D
           └─32674 /usr/local/sbin/keepalived -D
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: (Line 19) Truncating auth_pass to 8 characters
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: WARNING - script '/etc/keepalived/check_apiserver.sh' is not executable for uid:gid 0:0 - disabling.
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: SECURITY VIOLATION - scripts are being executed but script_security not enabled.
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: Assigned address 192.168.100.201 for interface eno1
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: Assigned address fe80::250:56ff:fe88:fd2 for interface eno1
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: Registering gratuitous ARP shared channel
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: (VI_1) removing VIPs.
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: (VI_1) Entering BACKUP STATE (init)
Sep 03 01:17:24 master02 Keepalived_vrrp[32674]: VRRP sockpool: [ifindex(2), family(IPv4), proto(112), unicast(0), fd(11,12)]
Sep 03 01:17:24 master02 systemd[1]: Started LVS and VRRP High Availability Monitor.
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/etc/systemd/system/keepalived.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2019-09-03 01:17:35 PDT; 14min ago
  Process: 16830 ExecStart=/usr/local/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 16831 (keepalived)
    Tasks: 2
   Memory: 648.0K
   CGroup: /system.slice/keepalived.service
           ├─16831 /usr/local/sbin/keepalived -D
           └─16832 /usr/local/sbin/keepalived -D
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: (Line 19) Truncating auth_pass to 8 characters
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: WARNING - script '/etc/keepalived/check_apiserver.sh' is not executable for uid:gid 0:0 - disabling.
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: SECURITY VIOLATION - scripts are being executed but script_security not enabled.
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: Assigned address 192.168.100.202 for interface eno1
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: Assigned address fe80::250:56ff:fe88:9624 for interface eno1
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: Registering gratuitous ARP shared channel
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: (VI_1) removing VIPs.
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: (VI_1) Entering BACKUP STATE (init)
Sep 03 01:17:35 master03 Keepalived_vrrp[16832]: VRRP sockpool: [ifindex(2), family(IPv4), proto(112), unicast(0), fd(11,12)]
Sep 03 01:17:35 master03 systemd[1]: Started LVS and VRRP High Availability Monitor.

haproxy

configuration

haproxy configure

$ sudo bash -c 'cat /etc/haproxy/haproxy.cfg' << EOF
#---------------------------------------------------------------------
# Example configuration for a possible web application.  See the
# full configuration options online.
#
#   http://haproxy.1wt.eu/download/2.0/doc/configuration.txt
#
#---------------------------------------------------------------------
#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    log         127.0.0.1 local2
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon
    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats
#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    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
#---------------------------------------------------------------------
# kubernetes apiserver frontend which proxys to the backends
#---------------------------------------------------------------------
frontend kubernetes-apiserver
    mode                 tcp
    bind                 *:16443
    option               tcplog
    default_backend      kubernetes-apiserver
#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend kubernetes-apiserver
    mode        tcp
    balance     roundrobin
    option      tcplog
    option      tcp-check
    server      ${master01Name} ${master01IP}:6443 check
    server      ${master02Name} ${master02IP}:6443 check
    server      ${master03Name} ${master03IP}:6443 check
#---------------------------------------------------------------------
# collection haproxy statistics message
#---------------------------------------------------------------------
listen stats
    bind                 :8000
    stats auth           admin:devops
    maxconn              50
    stats refresh        10s
    stats realm          HAProxy\ Statistics
    stats uri            /healthy
EOF

Service

$ sudo bash -c 'cat > /lib/systemd/system/haproxy.service' << EOF
[Unit]
Description=HAProxy Load Balancer
After=network.target syslog.service
Wants=syslog.service
[Service]
Environment="CONFIG=/etc/haproxy/haproxy.cfg" "PIDFILE=/run/haproxy.pid"
EnvironmentFile=-/etc/default/haproxy
ExecStartPre=/usr/sbin/haproxy -f $CONFIG -c -q
ExecStart=/usr/sbin/haproxy -W -f $CONFIG -p $PIDFILE $EXTRAOPTS
ExecReload=/usr/sbin/haproxy -f $CONFIG -c -q $EXTRAOPTS $RELOADOPTS
ExecReload=/bin/kill -USR2 $MAINPID
KillMode=mixed
Restart=always
Type=forking
[Install]
WantedBy=multi-user.target
EOF

Start Service

$ sudo systemctl enabled haproxy.service
$ sudo systemctl start haproxy.service

verify

$ sudo systemctl is-enabled haproxy.service
enabled
$ sudo systemctl is-active haproxy.service
active

Author: marslo
Article reference: https://imarslo.github.io/2020/09/10/1-15-3-HA-kubernetes-Cluster-Playbook-load-balance/
Copyright Notice: This website is licensed under CC BY-NC 4.0 . Please mark the derivation if you want to copy it: marslo » I, Marslo