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- CentOS 7 (minimum supported version);
- at least 2 GB of RAM and 2 CPUs per machine;
- opening doors on the control plane (6443, 2379-2380, 10250-10252) and on the worker (10250, 30000-32767);
- uniqueness uniqueness of MAC address and product_uuid for each node;
- complete connectivity between the cluster nodes;
- swap disabled on nodes.
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It's instructive to know which are the standard ports used by k8s and on which nodes (master, worker or, as we will see later, etcd) they must be opened. If you are using VMs instantiated thanks to OpenStack, it is not necessary to open these ports, because the machines communicate freely via their internal network. |
Now let's do a little study for the last 3 points of the list. Get the Let's start with MAC address and product_uuid of the cluster nodes, making sure they are different from each other, using the commands
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| language | bash |
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| title | MAC address and product_uuid |
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| collapse | true |
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# Equivalent commands to get MAC address (type format similar to "fa:16:3d:c9:ac:83")
$ ip link
$ ifconfig -a
# Command to get the product_uuid (type format similar to "92DD146C-F404-4253-J518-49602Z7C1B8F")
$ sudo cat /sys/class/dmi/id/product_uuid |
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| Code Block |
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| language | bash |
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| title | br_netfilter module |
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| collapse | true |
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# Verify that the br_netfilter module is present (you should get an output like the following)
$ lsmod | grep br_netfilter
br_netfilter 22256 0
bridge 151336 1 br_netfilter
# If not present, use
$ sudo modprobe br_netfilter |
As a requirement for your In order for a Linux node's iptables to correctly see view bridged traffic , you should ensure (see here), verify that net.bridge.bridge-nf-call-iptables is set to 1 in your sysctl config
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| language | bash |
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| title | iptables |
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| collapse | true |
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$ cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF |
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| language | bash |
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| title | Swap |
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| collapse | true |
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$ free -h
total used free shared buff/cache available
Mem: 3.7G 1.2G 223M 26M 2.3G 2.2G
Swap: 0B 0B 0B |
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