Lab Environment

Melanjutkan tahap sebelumnya membangun Kubernetes Cluster High Availability jika berjalan diatas openstack cluster. Namun kita bisa menerapkan ini pada environment virtual machine, cloud, maupun baremetal dengan melewati part 1.

Software Spec

SoftwareVersionDescription
Ubuntu20.04Operating System
KeepalivedlatestHigh Availability System
HAProxylatestHigh Availability System
KuberneteslatestContainer Orchestration
ContainerdlatestContainer Runtime Interface
CalicolatestContainer Network Interface

Networking Spec

Node NameIP AddressFloating IPDescription
k8s-apiserver192.168.0.10Int Load Balance Virtual IP
k8s-master01192.168.0.11Int Net
k8s-master02192.168.0.12Int Net
k8s-master03192.168.0.13Int Net
k8s-master01192.168.0.21172.16.0.21Int & Ext Net
k8s-master02192.168.0.22172.16.0.22Int & Ext Net
k8s-master03192.168.0.23172.16.0.23Int & Ext Net

Rancangan Topologi

image

Inisialisasi cluster Kubernetes pada semua node

Membuat dan mendistribusikan ssh public key

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ssh-keygen -t rsa -b 4096 -f ~/.ssh/id_rsa -qN ""
for i in {11,12,13,21,22,23}; do ssh-copy-id ubuntu@192.168.0.$i; done

Mapping hostname

Memetakan alamat ip dengan hostname node

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cat <<EOF | sudo tee -a /etc/hosts
192.168.0.10 k8s-apiserver
192.168.0.11 k8s-master01
192.168.0.12 k8s-master02
192.168.0.13 k8s-master03

192.168.0.100 k8s-lb-ingress
192.168.0.21 k8s-worker01
192.168.0.22 k8s-worker02
192.168.0.23 k8s-worker03
EOF

Menginstall paket untuk kebutuhan High Availability

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sudo apt update && sudo apt install -y haproxy keepalived

Menerapkan HAProxy untuk sistem internal load balancer k8s-apiserver

Mengkonfigurasi HAproxy pada semua master node

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cat <<EOF | sudo tee -a /etc/haproxy/haproxy.cfg
frontend k8s-apiserver
        bind *:8443
        mode tcp
        option tcplog
        default_backend k8s-apiserver

backend k8s-apiserver
        mode tcp
        option tcp-check
        balance roundrobin
        default-server inter 10s downinter 5s rise 2 fall 2 slowstart 60s maxconn 250 maxqueue 256 weight 100
        server k8s-master01 192.168.0.11:6443 check
        server k8s-master02 192.168.0.12:6443 check
        server k8s-master03 192.168.0.13:6443 check
EOF

Lakukan penguijan konfigurasi dengan perintah sudo haproxy -f /etc/haproxy/haproxy.cfg -c jika tidak ada pesan error bisa langsung diterapkan konfiruasi yang baru dengan perintah berikut :

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sudo systemctl restart haproxy

Menerapkan keepalived untuk sistem failover

Mengkonfigurasi check script pada semua master node

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cat <<EOF | sudo tee /etc/keepalived/check_apiserver.sh
#!/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 192.168.0.10; then
    curl --silent --max-time 2 --insecure https://k8s-apiserver:8443/ -o /dev/null || errorExit "Error GET https://k8s-apiserver:8443/"
fi
EOF

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sudo chmod +x /etc/keepalived/check_apiserver.sh

Mengkonfigurasi keepalived pada k8s-master01

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cat <<EOF | sudo tee /etc/keepalived/keepalived.conf
global_defs {
    router_id LVS_DEVEL
    enable_script_security
}
vrrp_script check_apiserver {
  script "/etc/keepalived/check_apiserver.sh"
  interval 2
  weight 2
  rise 3
  fall 3
}

vrrp_instance k8s-apiserver {
    state BACKUP
    nopreempt
    interface ens3
    virtual_router_id 69
    priority 102
    authentication {
        auth_type PASS
        auth_pass R@hasiaD0n9
    } 
    unicast_src_ip 192.168.0.11
    unicast_peer {
      192.168.0.12
      192.168.0.13
    }
    virtual_ipaddress {
      192.168.0.10/24
    }
    track_script {
        check_apiserver
    }
}
EOF

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sudo systemctl restart keepalived

Mengkonfigurasi keepalived pada k8s-master02

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cat <<EOF | sudo tee /etc/keepalived/keepalived.conf
global_defs {
    router_id LVS_DEVEL
    enable_script_security
}
vrrp_script check_apiserver {
  script "/etc/keepalived/check_apiserver.sh"
  interval 2
  weight 2
  rise 3
  fall 3
}

vrrp_instance k8s-apiserver {
    state BACKUP
    nopreempt
    interface ens3
    virtual_router_id 69
    priority 101
    authentication {
        auth_type PASS
        auth_pass R@hasiaD0n9
    } 
    unicast_src_ip 192.168.0.12
    unicast_peer {
      192.168.0.13
      192.168.0.11
    }
    virtual_ipaddress {
      192.168.0.10/24
    }
    track_script {
        check_apiserver
    }
}
EOF

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sudo systemctl restart keepalived

Mengkonfigurasi keepalived pada k8s-master03

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cat <<EOF | sudo tee /etc/keepalived/keepalived.conf
global_defs {
    router_id LVS_DEVEL
    enable_script_security
}
vrrp_script check_apiserver {
  script "/etc/keepalived/check_apiserver.sh"
  interval 2
  weight 2
  rise 3
  fall 3
}

vrrp_instance k8s-apiserver {
    state BACKUP
    nopreempt
    interface ens3
    virtual_router_id 69
    priority 100
    authentication {
        auth_type PASS
        auth_pass R@hasiaD0n9
    } 
    unicast_src_ip 192.168.0.13
    unicast_peer {
      192.168.0.12
      192.168.0.11
    }
    virtual_ipaddress {
      192.168.0.10/24
    }
    track_script {
        check_apiserver
    }
}
EOF

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sudo systemctl restart keepalived

Tahap selanjutnya dalam membangun Kubernetes Cluster High Availability.

Sumber Referensi