Kubernetes MetalLB Loadbalancer with BGP mode

In this post, MetalLB will be used on-premise as a Load Balancer with BGP to expose services on Kubernetes to outsideworld. As you know, if you have applications run on Kubernetes which is on your on-premise, that needs to be exposed to the outsideworld, should use LoadBalancer which is a bit tricky. it is quite easy if your applications in cloud environment such as AWS, Azure, or Google Cloud. Otherwise, you have to do similar in your on-premise network, with MetalLB or HAproxy. You can see my previous post how to achieve this with HAProxy here. For this post, we are going to achieve the same thing with MetalLB. You can see the Figure below, basic concept of MetalLB.

MetalLB in BGP mode.

I am assuming that you have Kubernetes installed on your Infrastructure. You can start configuring Metal-lb on your Kubernetes with the instruction in the link. If you follow the steps in the link you should get the results like below. MetalLB runs speaker pods in each worker and master nodes and controller pod in one of the node. As I understood in the metalLB website each speaker node establishes a BGP connection with router.

[tesla@k8s-m1 ~]$ kubectl get pods -n metallb-system 
NAME                          READY   STATUS    RESTARTS   AGE
controller-57f648cb96-ncbww   1/1     Running   1          3h8m
speaker-5n2c4                 1/1     Running   0          3h8m
speaker-7mwx2                 1/1     Running   8          3h8m
speaker-c7fgm                 1/1     Running   0          3h8m
speaker-vxcbd                 1/1     Running   0          3h8m

Next step is creating a configmap named ‘config‘ in the namespace metallb-system.

Creating a Configmap named config in the namespace metallb-system

apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    peers:
    - peer-address: 10.5.100.254
      peer-asn: 65000
      my-asn: 65000
    address-pools:
    - name: default
      protocol: bgp
      avoid-buggy-ips: true
      addresses:
      - 10.5.120.0/24

I faced a problem that, without adding an option avoid-buggy-ips: true, MetalLB allocated the ip 10.5.120.0, which is network address.

Configuring BGP on “Intelligent” Home router

I am using the physical router EdgeRouterX in my home lab, which is able to run BGP protocol with ECMP.

configure 
set protocols bgp 65000 parameters router-id 10.5.100.254
set protocols bgp 65000 neighbor 10.5.100.20 remote-as 65000
set protocols bgp 65000 neighbor 10.5.100.21 remote-as 65000
set protocols bgp 65000 neighbor 10.5.100.22 remote-as 65000
set protocols bgp 65000 maximum-paths ibgp 6
commit
save
exit

As it is my home lab, I just picked one of the AS number(65000) that is in the private range. For more info on ASN number, check here.

Experiment:

After deploying MetalLB and configuring the Router with BGP, we can do some checks, if BGP peering successfully between the Kubernetes worker nodes and my Home router.

ubnt@ubnt-R0:~$ show ip bgp summary 
BGP router identifier 10.5.100.254, local AS number 65000
BGP table version is 27
1 BGP AS-PATH entries
0 BGP community entries
1  Configured ebgp ECMP multipath: Currently set at 1
6  Configured ibgp ECMP multipath: Currently set at 6

Neighbor                 V   AS   MsgRcv    MsgSen TblVer   InQ   OutQ    Up/Down   State/PfxRcd
10.5.100.20              4 65000  494        485      27      0      0  03:25:32               1
10.5.100.21              4 65000  409        423      27      0      0  03:17:29               1
10.5.100.22              4 65000  494        486      27      0      0  03:25:32               1

Total number of neighbors 3

Total number of Established sessions 3

Checking the logs in one of speaker pod.

[tesla@k8s-m1 ~]$ kubectl logs -f  -n metallb-system speaker-5n2c4 
{"caller":"bgp_controller.go:232","event":"updatedAdvertisements","ip":"10.5.120.1","msg":"making advertisements using BGP","numAds":1,"pool":"default","protocol":"bgp","service":"default/nginx","ts":"2020-08-30T09:59:48.873159314Z"}

Creating a Sample Deployment

Last step is to creating a sample deployment to check if MetalLB works as expected.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1
        ports:
        - name: http
          containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx
spec:
  ports:
  - name: http
    port: 8080
    protocol: TCP
    targetPort: 80
  selector:
    app: nginx
  type: LoadBalancer

[tesla@k8s-m1 ~]$ kubectl get deployments.apps 
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   1/1     1            1           145m
[tesla@k8s-m1 ~]$ kubectl get svc nginx 
NAME    TYPE           CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
nginx   LoadBalancer   10.96.136.46   10.5.120.1    8080:30169/TCP   88m
gokay@angora:~$ curl http://10.5.120.1:8080 
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

The last but not least, I had a problem while trying to access to application from KVM host. VMs are able to reach without an issue. I solved the problem, once I added default gateway for my ‘Intelligent’ router.

default via 10.5.100.254 dev br100 > My ‘Intelligent router’
default via 192.168.0.1 dev wlp4s0 proto dhcp metric 600 > ‘My Wifi Router’

Creating Bridges and VLANs with Netplan

In this post, It will be demonstrated how to create Bridges and VLANs to be used on KVM. In my other post, I already implemented VLANs using Openvswitch.

Physical host that I used on this lab is Linux Mint 20 (Ulyana).

Netplan is a utility for easily configuring networking on a GNU/Linux systems. You can easily create network configuration with YAML syntax. Netplan reads network configuration from /etc/netplan/*.yaml which are written by administrators, installers, cloud image instantiations, or other OS deployments.

Prerequisite:

Before starting any configuration you have to load the module 8021q, if it is not loaded. For Linux Mint 20 it is loaded automatically on boot.

Creating a netplan configuration File:

Create a file in the /etc/netplan/bridge.yaml and copy the content below. Of course you can change the configuration based on your needs.

network:
  version: 2
  renderer: networkd
  ethernets:
    enp5s0:
      dhcp4: no
  bridges:
    VSW0:
      interfaces: [ enp5s0 ]
      dhcp4: false
      dhcp6: false
      parameters:
        forward-delay: 0
        stp: true
    br10:
      interfaces: [ vlan.10 ]
      dhcp4: false
      dhcp6: false
      addresses: []
      parameters:
        forward-delay: 0
        stp: true
    br20:
      interfaces: [ vlan.20 ]
      dhcp4: false
      dhcp6: false
      addresses: []
      parameters:
        forward-delay: 0
        stp: false
    br100:
      interfaces: [ vlan.100 ]
      dhcp4: false
      dhcp6: false
      addresses: []
      parameters:
        forward-delay: 0
        stp: true
  vlans:
    vlan.10:
      id: 10
      link: enp5s0
      dhcp4: false
      dhcp6: false
    vlan.20:
      id: 20
      link: enp5s0
      dhcp4: false
      dhcp6: false
    vlan.100:
      id: 100
      link: enp5s0
      dhcp4: false
      dhcp6: false

After netplan config created , syntax check should be made before apply the configuration.

gokay@tesla:~$ sudo netplan try
Please carefully review the configuration and use 'netplan apply' directly.
gokay@tesla:~$ sudo netplan apply

Once the configuration applied, bridges and vlan interfaces should be created. You can check it with the utility brctl.

gokay@tesla:~$ sudo brctl show
bridge name	bridge id		STP enabled	interfaces
VSW0		8000.244bfe0502f8	yes		enp5s0
br10		8000.244bfe0502f8	yes		vlan.10
br100		8000.244bfe0502f8	yes		vlan.100
							vnet0
br20		8000.244bfe0502f8	no		vlan.20

You can simply see the Figure below to understand easily how our physical host looks like now. In this post, you can ignore the Physical switch and Router part, as we did not do any Physical switch and Router configuration for Intervlan routing.

Once netplan configuration has been completed, you can check on virt-manager if you are able to see the bridges(VLANs)

Experiment:

On the VM, I just ping the IP that does not allocated by any machine to create a Broadcast package to sniff via Wireshark.

I pinged to 10.5.100.23 from 10.5.100.10(VM) .

As you see in the figure above, You can see the frame 802.1q section. Which means vlan configured successfully.

Finding Server IMM IP by IPv6 Multicast Address

Sometimes you may have a situation that IMM does not have a L3 connection that you need to go to Data-center and connect from your laptop to server IMM interface via Ethernet cable. Imagine a situation that your organization infrastructure was not documented very well that you do not know the IPv4 address of IMM interface to login.

If server IMM interface enabled with IPv6, then you are lucky — By using below methods you can easily figure out the IPv6 address of IMM interface and use it to connect to login IMM.

In this method by pinging IPv6 Link Local Scope multicast address(ff02::1), we are listing all the clients that joined to multicast group. According to Figure above ping will list only two multicast addresses that are your laptop and Server. Once we find server IPv6 Link local address on IMM interface, you can try to use login web browser by typing IPv6 Link local address which is fe80::5667:51ff:feb9:4ade%eth0 in that case. If it does not work, you can then use SSH Local Port Forwarding like below.

# ssh  -L 9090:[fe80::5667:51ff:feb9:4ade%eth0]:443 127.0.0.1

Open up the web browser and type https://127.0.0.1:9090

On windows; first find the interface ID with the below command. For this lab it is going to be used Wi-Fi (13)

netsh int ipv4 show interfaces

Idx     Met         MTU          State                Name
---  ----------  ----------  ------------  ---------------------------
  1          75  4294967295  connected     Loopback Pseudo-Interface 1
 13          55        1500  connected     Wi-Fi
 11          25        1500  connected     Ethernet
 12           5        1500  disconnected  Ethernet 2
 10          35        1500  connected     VMware Network Adapter VMnet1
  4          25        1500  disconnected  Local Area Connection* 4
 17          35        1500  connected     VMware Network Adapter VMnet8


ping -6 ff02::1%13

Note: You may get “Request time out.” when you try to ping multicast address on specified interface on Windows. But when you capture package via Wireshark, it still shows all the neighbor devices that joined multicast group.

Highly available Load-balancer for Kubernetes Cluster On-Premise – II

In the first post of this series, haproxy and keepalived installed, configured and tested.

In this post, two stateless Kubernetes web application will be deployed and domain names will be registered to DNS for these two web applications to test if Load-balancer is working as expected.

Note: For my home-lab, I am using the domain nordic.io.

For the Kubernetes cluster, I am assuming that, nginx Ingress controller deployed as DaemonSet and listening on port 80 and port 443 on each worker node.

Deploying Kubernetes Web Applications:

apiVersion: v1
kind: Service
metadata:
  name: hello-kubernetes-svc
  namespace: default
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: hello-kubernetes
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-kubernetes
spec:
  replicas: 3
  selector:
    matchLabels:
      app: hello-kubernetes
  template:
    metadata:
      labels:
        app: hello-kubernetes
    spec:
      containers:
      - name: hello-kubernetes
        image: paulbouwer/hello-kubernetes:1.8
        ports:
        - containerPort: 8080
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: hello-kubernetes-ingress
  annotations:
    ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: helloworld.nordic.io  
    http:
      paths:
        - path: /
          backend:
            serviceName: hello-kubernetes-svc
            servicePort: 80

apiVersion: v1
kind: Service
metadata:
  name: whoami-svc
  namespace: default
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    run: whoami
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    run: whoami
  name: whoami
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      run: whoami
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      labels:
        run: whoami
    spec:
      containers:
      - image: yeasy/simple-web:latest
        name: whoami
      restartPolicy: Always
      schedulerName: default-scheduler
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: whoami-ingress
  annotations:
    ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: whoami.nordic.io  
    http:
      paths:
        - path: /
          backend:
            serviceName: whoami-svc
            servicePort: 80

Registering Web Apps to DNS:

Adding DNS Records one of the curial part. In order to use single Load Balancer IP to multiple services we are adding CNAME record. You can see bind dns configuration below to make it.

vip1 IN A 10.5.100.50
helloworld IN CNAME vip1
whoami IN CNAME vip1

Experiment:

Checking DNS Records.

[tesla@deployment ~]$ nslookup helloworld
Server:		10.5.100.253
Address:	10.5.100.253#53

helloworld.nordic.io	canonical name = vip1.nordic.io.
Name:	vip1.nordic.io
Address: 10.5.100.50

[tesla@deployment ~]$ nslookup whoami
Server:		10.5.100.253
Address:	10.5.100.253#53

whoami.nordic.io	canonical name = vip1.nordic.io.
Name:	vip1.nordic.io
Address: 10.5.100.50

Testing Services:

Hello World App:

Whoami App:

Highly available Load-balancer for Kubernetes Cluster On-Premise – I

In this post, we are going to build highly available HAProxy Load-balancer for our Kubernetes cluster on-premise. For this, HaProxy will be used for external Load-balancer which takes the requests from outside world sends them to Kubernetes worker nodes on which nginx ingress controller listens incoming requests on port 80 and 443.

Another curial software component is Keepalived which provides a highly available HAProxy load-balancer, in case of any of HAProxy loadbalancer is down.

Keepalived is a Robust Virtual Router Redundancy Protocal (VRRP )implementation in GNU/Linux

To build cluster, Ubuntu 18.04.4 used. You can see below diagram how environment looks like.

Installing necessary Software Suits

# sudo apt-get install haproxy
# sudo apt-get install keepalived
# sudo systemctl enable haproxy
# sudo systemctl enable keepalived

Configuring Necessary Kernel Parameters

The below configuration is very important to implement it on both nodes.

In order for the Keepalived service to forward network packets properly to the real servers, each node must have IP forwarding turned on in the kernel. Log in as root and change the line which reads net.ipv4.ip_forward = 0 in /etc/sysctl.conf to the following:

net.ipv4.ip_forward = 1

The changes take effect when you reboot the system. Load balancing in HAProxy and Keepalived at the same time also requires the ability to bind to an IP address that are nonlocal, meaning that it is not assigned to a device on the local system. This allows a running load balancer instance to bind to an IP that is not local for failover. To enable, edit the line in /etc/sysctl.conf that reads net.ipv4.ip_nonlocal_bind to the following:

net.ipv4.ip_nonlocal_bind = 1

The changes take effect when you reboot the system.

Configuring Keepalived on both nodes

Some keepalived settings has to be changed accordingly in the second node. So, check the commented lines in the keepalived.conf

global_defs {
   notification_email {
     admin@manintheit.org
   }
   notification_email_from keepalived@manintheit.org
   smtp_server localhost
   smtp_connect_timeout 30
   router_id ha1 #router_id ha2 on the second node(ha2)
   vrrp_skip_check_adv_addr
   vrrp_garp_interval 0.5
   vrrp_garp_master_delay 1
   vrrp_garp_master_repeat 5
   vrrp_gna_interval 0
   enable_script_security
   script_user root
   vrrp_no_swap
   checker_no_swap
}

# Script used to check if HAProxy is running
vrrp_script check_haproxy {
       script "/usr/bin/pgrep haproxy 2>&1 >/dev/null"
        interval 1
        fall 2
        rise 2
}

# Virtual interface
vrrp_instance VI_01 {
        state MASTER #state BACKUP on the second node(ha2)
        interface enp1s0
        virtual_router_id 120
        priority 101  #priority 100 on the second node(ha2). Higher number wins.
        nopreempt
        advert_int 1
        unicast_src_ip 10.5.100.51  #unicast_src_ip 10.5.100.52 on the second node(ha2)
        unicast_peer {
                10.5.100.52    #unicast_peer 10.5.100.51 on the second (ha2)
        }
        virtual_ipaddress {
                10.5.100.50/24 dev enp1s0 label enp1s0:ha-vip1
        }
        authentication {
                auth_type PASS
                auth_pass MANINTHEIT
        }
        track_script {
                check_haproxy
        }
}

HAProxy Config

#Default configurations in the haproxy.cfg has been omitted.

frontend stats
    bind 10.5.100.51:9000
    mode http
    maxconn 10
    stats enable
    stats show-node
    stats hide-version
    stats realm Haproxy\ Statistics
    stats uri /hastats
    stats auth haadmin:haadmin

frontend k8s-service-pool
  mode tcp
  bind 10.5.100.50:80
  default_backend k8s-service-backend

backend k8s-service-backend
    mode tcp
    balance source
    server k8s-worker-01 10.5.100.21 check port 80 inter 10s rise 1 fall 2 
    server k8s-worker-02 10.5.100.22 check port 80 inter 10s rise 1 fall 2
    server k8s-worker-03 10.5.100.23 check port 80 inter 10s rise 1 fall 2

Restart the service keepalived and haproxy on both nodes.

# sudo systemctl restart haproxy
# sudo systemctl restart keepalived

Experiment:

1- Lets check with tcpdump utility if master node sends VRRP advertisement packets to every second to all members of VRRP group.

# tcpdump proto 112 -n

2- Lets check interface IPs; As you see, first node(ha1) looks active node as it register to VIP 10.5.100.50.

Second Part of the Post will be published soon, Stay healthy!

Hourly logrotation

Sometimes, you need to rotate your logs hourly instead of daily or weekly, if you have a big virtual environment many things needs to be logged. Sometimes daily logs are so huge that you need hourly log-rotation. For this one you need to customize some of the settings in your central syslog server. You can find the sample steps below to create logrotate configuration that rotates the logs hourly.

Steps:

1 – Copy /etc/cron.daily/logrotate to /etc/cron.hourly and set it as executable.

# cp /etc/cron.daily/logrotate /etc/cron.hourly
# chmod u+x /etc/cron.hourly/logrotate

2- Create a folder logrotate.hourly.conf in /etc

# mkdir -p /etc/logrotate.hourly.conf

3- Modify the file logrotate in the /etc/cron.hourly based on your needs. See below for sample.

#!/bin/sh
/usr/sbin/logrotate /etc/logrotate.hourly.conf/example
EXITVALUE=$?
if [ $EXITVALUE != 0 ]; then
    /usr/bin/logger -t logrotate "ALERT exited abnormally with [$EXITVALUE]"
fi
exit $EXITVALUE

3- Create your logrotate script in the folder /etc/logrotate.hourly.conf

For this post, we named it as ‘example’. (We also specified it in the configuration /etc/logrotate.hourly.conf/logrotate)

/opt/logs/[2-9][0-9][0-9][0-9]/[0-9][0-9]/[0-9][0-9]/*.log {
    notifempty
    compress
    maxage 60
    rotate 200
    create 0600 root root
    size 4G
    postrotate
        /usr/bin/systemctl reload syslog-ng > /dev/null
    endscript
}

  • You may need to tune up rotate, size and maxage options base on your needs.

LACP Configuration with Cumulux VX Virtual Appliances

In this post LACP will be configured on Cumulus VX virtual appliance. Test simulated on GNS3 Network simulation.

Sample Topology

This is the sample network topology to test LACP.

Configuration on Both Virtual Appliances for LACP

In this configuration, swp1 and swp2 ports used as a slave ports of LAGG0 on both switches.

cumulus@cumulus:~$ net add bond LAGG0 bond slaves swp1,2
cumulus@cumulus:~$ net add bond LAGG0 bond mode 802.3ad
cumulus@cumulus:~$ net add bond LAGG0 bond lacp-rate slow
cumulus@cumulus:~$ net add bond LAGG0 bond miimon 100

Configuration on Both Virtual Appliances for VLAN configuration

In below configuration, VLAN 10 added to bridge(on cumulus vlan-aware bridge) and swp3 configured as an access port with VLAN id 10.

cumulus@cumulus:~$ net add bridge bridge vlan-protocol 802.1ad
cumulus@cumulus:~$ net add bridge bridge ports LAGG0
cumulus@cumulus:~$ net add bridge bridge ports swp3
cumulus@cumulus:~$ net add bridge bridge vids 10
cumulus@cumulus:~$ net add interface swp3 bridge access 10

Experiment

It is also tested that after one of the link has been cut, host still able to ping to other end without any package drop.

Run VMware PowerCLI on your Docker Container

If you have a vSphere environment in your Infrastructure and want to automate provisioning steps, you are most likely need PowerCLI which mostly requires Windows Guest or supported GNU/Linux guest on your environment. By the way, Terraform also very nice tool to provision new virtual machine, but it is very limited.

If you stumble upon the same case above, this post for you. Actually you do not need any GNU/Linux or Window guest but docker. If you have a docker environment you can pull vmware/powerclicore image, run it in your docker environment and connect your vcenter server in that docker container.

I used it to set boot priority of virtual guests. One of the good thing with docker is that you can also pass your environment variables inside the container to use that variables.

docker run  --rm -it --entrypoint="/usr/bin/pwsh"  \
   -e VI_SERVER=${TF_VAR_vsphere_server} \
   -e VI_USERNAME=${TF_VAR_vsphere_user} \
   -v ${pwd}/scripts:/tmp/scripts vmware/powerclicore /tmp/scripts/setboot-priority.ps1

What above shell script does that, it instantiates docker image vmware/powerclicore mounts <pwd>/scripts/ folder(where config.txt and setboot-priority.ps1 lives) on the host to /tmp/scripts in the container and run setboot-priority.ps1 in the container.

You can get setboot-priority.ps1 script from my github repo.

Creating a Image for MaaS with Packer

In this post we are going to build an image with Packer which will be used to deploy via MaaS. After image built and uploaded to MaaS, it can be used to provision virtual machine or deploy OS on Bare-Metal machines. In order to build an image that is deployable with MaaS, we need couple of files which you can clone here.

For this post, It will be created minimal CentOS7 image including httpd package to test. One of the cool thing is with Packer that you can also run execute your Ansible playbook inside the machine being provisioned by Packer. Ansible(remote) provisioner is used to configure ntp server and install httpd.

As Qemu used as a builder, qemu-system-x64 has to be installed on the host where Packer runs. Packer will create an qcow2 image after successful image creation. But we are going to use tar.gz image file as we deploy image via MaaS.

centos7.json (do not forget to change iso_url in accordance with your environment.)

{
    "builders": [
        {
            "type": "qemu",
	    "iso_url": "/home/tesla/packer/centos7/isos/CentOS-7-x86_64-NetInstall-2003.iso",
            "iso_checksum_type": "sha256",
	    "iso_checksum": "101bc813d2af9ccf534d112cbe8670e6d900425b297d1a4d2529c5ad5f226372",
            "boot_command": [
                "<tab> ",
                "inst.ks=http://{{ .HTTPIP }}:{{ .HTTPPort }}/centos7.ks ",
                "<enter>"
            ],
	    "ssh_username": "tesla",
	    "ssh_password": "tesla",
	    "ssh_wait_timeout": "12000s",
            "boot_wait": "3s",
            "disk_size": "4G",
	    "display": "none",
            "headless": false,
            "memory": 4096,
	    "accelerator": "kvm",
	    "cpus": 4,
            "http_directory": "http",
            "shutdown_timeout": "20m",
	    "disk_interface": "virtio",
            "format": "qcow2",
            "net_device": "virtio-net"

        }
    ],

"post-processors": [
        {
            "type": "shell-local",
            "inline_shebang": "/bin/bash -e",
            "inline": [
                "TMP_DIR=$(mktemp -d /tmp/packer-maas-XXXX)",
                "echo 'Mounting image...'",
                "modprobe nbd",
                "qemu-nbd -d /dev/nbd4",
                "qemu-nbd -c /dev/nbd4 -n output-qemu/packer-qemu",
                "echo 'Waiting for partitions to be created...'",
                "tries=0",
                "while [ ! -e /dev/nbd4p1 -a $tries -lt 60 ]; do",
                "    sleep 1",
                "    tries=$((tries+1))",
                "done",
                "echo 'Tarring up image...'",
                "mount /dev/nbd4p1 $TMP_DIR",
                "tar -Sczpf centos7.tar.gz --selinux -C $TMP_DIR .",
                "echo 'Unmounting image...'",
                "umount $TMP_DIR",
                "qemu-nbd -d /dev/nbd4",
                "rmdir $TMP_DIR"
            ]
        }
    ],
    "provisioners": [
    {
  "type": "shell",
  "pause_before": "5s",
  "inline": [
	"sudo yum -y install epel-release",
	"sudo yum -y update",
	"sudo yum -y remove cloud-init",
	"sudo yum -y install python-jsonschema python-devel",
	"sudo yum -y install cloud-init --disablerepo=* --enablerepo=group_cloud-init-el-stable",
	"sudo yum -y install qemu-guest-agent wget"
  ]
},
    {
      "user": "tesla",
      "type": "ansible",
      "playbook_file": "./ansible/main.yml"
    },
    {
     "type": "shell",
     "inline": [
     
	"sudo systemctl enable cloud-init",
	"sudo rm -rf /var/lib/cloud/",
	"sudo rm -rf /etc/cloud/cloud-init.disabled",
	"sudo /usr/bin/truncate -s 0 /etc/fstab",
	"sudo /usr/bin/truncate -s 0 /etc/resolv.conf",
        "sudo rm -f /etc/sysconfig/network-scripts/ifcfg-[^lo]*",
        "sudo sync"
  ]
}
    ]
}
#main.yml
---
- hosts: default
  become: yes
  roles:
    - configure_httpd
    - configure_chrony

centos7.ks

url --mirrorlist="http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os"
text
reboot
firewall --enabled --service=ssh,http
firstboot --disable
ignoredisk --only-use=vda
lang en_US.UTF-8
keyboard us
network --bootproto=dhcp --hostname=packer-maas.manintheit.org
selinux --enforcing
timezone UTC --isUtc
bootloader --location=mbr --driveorder="vda" --timeout=1
rootpw --plaintext root1234
user --name=tesla --groups=wheel --plaintext --password=tesla


repo --name="Base" --mirrorlist="http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os"
repo --name="Updates" --mirrorlist="http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=updates"
repo --name="Extras" --mirrorlist="http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras"
repo --name="cloud-init" --baseurl="http://copr-be.cloud.fedoraproject.org/results/@cloud-init/el-stable/epel-7-x86_64"

zerombr
clearpart --all --initlabel
part / --size=1 --grow --asprimary --fstype=ext4


%packages
@core
#httpd
bash-completion
cloud-init-el-release
cloud-init
# cloud-init only requires python-oauthlib with MAAS. As such upstream
# has removed python-oauthlib from cloud-init's deps.
python2-oauthlib
cloud-utils-growpart
rsync
tar
yum-utils
# bridge-utils is required by cloud-init to configure networking. Without it
# installed cloud-init will try to install it itself which will not work in
# isolated environments.
bridge-utils
# Tools needed to allow custom storage to be deployed without acessing the
# Internet.
grub2-efi-x64
shim-x64
# Older versions of Curtin do not support secure boot and setup grub by
# generating grubx64.efi with grub2-efi-x64-modules.
grub2-efi-x64-modules
efibootmgr
dosfstools
lvm2
mdadm
device-mapper-multipath
iscsi-initiator-utils
-plymouth
# Remove ALSA firmware
-a*-firmware
# Remove Intel wireless firmware
-i*-firmware
%end


%post --erroronfail
systemctl disable cloud-init
touch /etc/cloud/cloud-init.disabled
yum install -y sudo
echo "tesla        ALL=(ALL)       NOPASSWD: ALL" >> /etc/sudoers.d/tesla
sed -i "s/^.*requiretty/#Defaults requiretty/" /etc/sudoers
yum clean all
%end

Validating Packer config.

sudo PACKER_LOG=1 packer validate centos7.json

After successful validation, we can start building machine image.

sudo PACKER_LOG=1 packer build centos7.json

Once packer finished successfully, centos7.tar.gz file should be created, which will be uploaded to MaaS to provision VMs or Install OS in Bare-Metal servers.

Uploading image to MaaS.

maas $PROFILE boot-resources create name="centos/centos7Packer1" architecture=amd64/generic content@=centos7.tar.gz

Important Takeaways on Packer.

Do not forget to issue sync command inside machine provisioned by Packer. Otherwise, you will experience with the empty systemd unit files. So, sync command will flush data from cache to disk.

As MaaS uses cloud-init to setup various host settings such as partitioning disk, dns server, network configuration etc. Some of the files are removed or truncated prior to image creation. Because MaaS will populate these configurations during the first boot of the system. If you deploy the OS via MaaS, configure dns setting on the MaaS, it will be anyway overwritten by cloud-init even, you configure resolv.conf inside the image.

Provisioning a VM on KVM via Kickstart using virt-install

virt-install is a command line tool for creating new KVM , Xen, or Linux container guests using the “libvirt” hypervisor management library. It is one of the quickest way to deploy a vm from the command line. In this post I will also show you to install CentOS on KVM via kickstart. In this installation instead of choosing native GNU/Linux bridge we are using Open Vswitch.

For your environment, I am assuming that you already configured your dhcp, dns and http server environment for the pxeboot. I am using cobbler for dhcp server management. I am provisioning CentOS machines for installation of Kubernetes Cluster nodes. As I use remote KVM host, user tesla has to able to connect with SSH key authentication and the user tesla has to be in the group libvirt.

Provisioning script.

virt-install \
--connect qemu+ssh://tesla@192.168.122.1/system \
--name k8s-master \
--ram 2048 \
--disk bus=virtio,pool=KVMGuests,size=15,format=qcow2 \
--network network=OVS0,model=virtio,virtualport_type=openvswitch,portgroup=VLAN100 \
--vcpus 2 \
--os-type linux \
--location http://cobbler.manintheit.org/cblr/links/CentOS7-x86_64 \
--os-variant rhel7 \
--extra-args="ks=http://10.5.100.253/k8s/k8s-master-centos7.ks ksdevice=eth0 ip=10.5.100.15 netmask=255.255.255.0 dns=10.5.100.253 gateway=10.5.100.254" 
--location Distribution tree installation source. virt-install can recognize certain distribution trees and fetches a bootable kernel/initrd pair to launch the install.

k8s-master-centos7.ks

install
text
eula --agreed
url --url=http://10.5.100.253/cblr/links/CentOS7-x86_64/
lang en_US.UTF-8
keyboard us
network --onboot=on --bootproto=static  --ip 10.5.100.15 --netmask 255.255.255.0 --gateway 10.5.100.254 --nameserver 10.5.100.253 --device=eth0 --hostname k8s-master.manintheit.org
rootpw root
firewall --disabled
selinux --permissive
timezone Europe/Berlin
skipx
zerombr
clearpart --all --initlabel
part /boot --fstype ext4 --size=512
part /     --fstype ext4 --size=1 --grow
authconfig --enableshadow --passalgo=sha512
services --enabled=NetworkManager,sshd
reboot
user --name=tesla --plaintext --password tesla --groups=tesla,wheel

#repo --name=base --baseurl=http://mirror.centos.org/centos/7.3.1611/os/x86_64/
#repo --name=epel-release --baseurl=http://anorien.csc.warwick.ac.uk/mirrors/epel/7/x86_64/
#repo --name=elrepo-kernel --baseurl=http://elrepo.org/linux/kernel/el7/x86_64/
#repo --name=elrepo-release --baseurl=http://elrepo.org/linux/elrepo/el7/x86_64/
#repo --name=elrepo-extras --baseurl=http://elrepo.org/linux/extras/el7/x86_64/

%packages --ignoremissing --excludedocs
@Base
%end

%post
yum update -y
yum install -y sudo
echo "tesla        ALL=(ALL)       NOPASSWD: ALL" >> /etc/sudoers.d/tesla
sed -i "s/^.*requiretty/#Defaults requiretty/" /etc/sudoers
/bin/echo 'UseDNS no' >> /etc/ssh/sshd_config
yum clean all
/bin/sh -c 'echo "br_netfilter" > /etc/modules-load.d/br_netfilter.conf'
modprobe br_netfilter
cat <<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system

#Enable kubernetes repo
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
%end