TLS authentication

Overview

If necessary, issue a private TLS certificate so that only clients with that TLS certificate can use the ETCD3. You can access the cluster and force it to perform data CRUD.

Create a certificate

Install the necessary tools

cfssl, cfssljson installation

#!/bin/bash
CFSSL_VERSION=1.6.5
CFSSL_PATH=/usr/local/bin
ARCH=amd64

curl -L "https://github.com/cloudflare/cfssl/releases/download/v${CFSSL_VERSION}/cfssl_${CFSSL_VERSION}_linux_${ARCH}" -o cfssl
curl -L "https://github.com/cloudflare/cfssl/releases/download/v${CFSSL_VERSION}/cfssljson_${CFSSL_VERSION}_linux_${ARCH}" -o cfssljson
curl -L "https://github.com/cloudflare/cfssl/releases/download/v${CFSSL_VERSION}/cfssl-certinfo_${CFSSL_VERSION}_linux_${ARCH}" -o cfssl-certinfo

chmod +x cfssl cfssljson cfssl-certinfo
sudo cp cfssl cfssljson cfssl-certinfo ${CFSSL_PATH}/

Issue a certificate

Note

Refer to the Certificate Issuance Example for ETCD3 Clusters.

https://github.com/etcd-io/etcd/tree/main/hack/tls-setup

Modify the Makefile as needed, as shown below.

On this example, the name template is changed for the .pem file that is generated by exporting with the cfssljson command for ease of file management.

$ vim Makefile
.PHONY: cfssl ca req clean

CFSSL   = @env PATH=$(GOPATH)/bin:$(PATH) cfssl
JSON    = env PATH=$(GOPATH)/bin:$(PATH) cfssljson

all:  ca req

cfssl:
        HTTPS_PROXY=127.0.0.1:12639 go get -u -tags nopkcs11 github.com/cloudflare/cfssl/cmd/cfssl
        HTTPS_PROXY=127.0.0.1:12639 go get -u github.com/cloudflare/cfssl/cmd/cfssljson
        HTTPS_PROXY=127.0.0.1:12639 go get -u github.com/mattn/goreman

ca:
        mkdir -p certs
        $(CFSSL) gencert -initca config/ca-csr.json | $(JSON) -bare certs/etcd-ca

req:
        $(CFSSL) gencert \
          -ca certs/etcd-ca.pem \
          -ca-key certs/etcd-ca-key.pem \
          -config config/ca-config.json \
          config/req-csr.json | $(JSON) -bare certs/${infra0}
        $(CFSSL) gencert \
          -ca certs/etcd-ca.pem \
          -ca-key certs/etcd-ca-key.pem \
          -config config/ca-config.json \
          config/req-csr.json | $(JSON) -bare certs/${infra1}
        $(CFSSL) gencert \
          -ca certs/etcd-ca.pem \
          -ca-key certs/etcd-ca-key.pem \
          -config config/ca-config.json \
          config/req-csr.json | $(JSON) -bare certs/${infra2}
        $(CFSSL) gencert \
          -ca certs/etcd-ca.pem \
          -ca-key certs/etcd-ca-key.pem \
          -config config/ca-config.json \
          config/req-csr.json | $(JSON) -bare certs/${infra0}-peer
        $(CFSSL) gencert \
          -ca certs/etcd-ca.pem \
          -ca-key certs/etcd-ca-key.pem \
          -config config/ca-config.json \
          config/req-csr.json | $(JSON) -bare certs/${infra1}-peer
        $(CFSSL) gencert \
          -ca certs/etcd-ca.pem \
          -ca-key certs/etcd-ca-key.pem \
          -config config/ca-config.json \
          config/req-csr.json | $(JSON) -bare certs/${infra2}-peer

clean:
        rm -rf certs

Modify the certificate CSR (Certificate Signing Request) as needed, as shown below.

Delete the "CN" entry. The Python gRPC gateway that Patroni currently uses as a client to access ETCDs does not support certificates with TLS Common Name applied.
In the host entry, enter the IP address and hostname (if necessary) of the ETCD cluster to be configured as an array.

$ vim config/req-csr.json
{
  "CN": "etcd",               # Delete the Patroni -> etcd connection if you have an encrypted configuration
  "hosts": [
    "localhost",
    "127.0.0.1",
    "node1",
    "node2",
    "node3",
    "172.176.0.2",
    "172.176.0.3",
    "172.176.0.4"
  ],
  "key": {
    "algo": "ecdsa",
    "size": 384
  },
  "names": [
    {
      "O": "autogenerated",
      "OU": "etcd cluster",
      "L": "the internet"
    }
  ]
}

Modify the certificate authority (CA) CSR as needed, as shown below.

Delete “CN” entry.
Modify the names entry as needed, as shown below.

$ vim config/ca-csr.json
{
  "CN": "Autogenerated CA",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "O": "TmaxTibero",
      "OU": "OpenSQL",
      "L": "Seongnam-si",
      "ST": "Gyeonggi-do",
      "C": "KR"
    }
  ]
}

Execute make to generate the certificate.

The values of the infra0, infra1, and infra2 environment variables you set are used as file names for the generated .pem certificate.

$ infra0=node1 infra1=node2 infra2=node3 make

$ ls -l
total 84
-rw-r--r-- 1 yhyjeon yhyjeon  985  1월  6 18:10 etcd-ca.csr
-rw------- 1 yhyjeon yhyjeon 1679  1월  6 18:10 etcd-ca-key.pem
-rw-rw-r-- 1 yhyjeon yhyjeon 1281  1월  6 18:10 etcd-ca.pem
-rw-r--r-- 1 yhyjeon yhyjeon  623  1월  6 18:10 node1.csr
-rw------- 1 yhyjeon yhyjeon  288  1월  6 18:10 node1-key.pem
-rw-rw-r-- 1 yhyjeon yhyjeon 1196  1월  6 18:10 node1.pem
-rw-r--r-- 1 yhyjeon yhyjeon  623  1월  6 18:10 node2.csr
-rw------- 1 yhyjeon yhyjeon  288  1월  6 18:10 node2-key.pem
-rw-rw-r-- 1 yhyjeon yhyjeon 1196  1월  6 18:10 node2.pem
-rw-r--r-- 1 yhyjeon yhyjeon  623  1월  6 18:10 node3.csr
-rw------- 1 yhyjeon yhyjeon  288  1월  6 18:10 node3-key.pem
-rw-rw-r-- 1 yhyjeon yhyjeon 1196  1월  6 18:10 node3.pem
-rw-r--r-- 1 yhyjeon yhyjeon  623  1월  6 18:10 node1-peer.csr
-rw------- 1 yhyjeon yhyjeon  288  1월  6 18:10 node1-peer-key.pem
-rw-rw-r-- 1 yhyjeon yhyjeon 1196  1월  6 18:10 node1-peer.pem
-rw-r--r-- 1 yhyjeon yhyjeon  623  1월  6 18:10 node2-peer.csr
-rw------- 1 yhyjeon yhyjeon  288  1월  6 18:10 node2-peer-key.pem
-rw-rw-r-- 1 yhyjeon yhyjeon 1196  1월  6 18:10 node2-peer.pem
-rw-r--r-- 1 yhyjeon yhyjeon  623  1월  6 18:10 node3-peer.csr
-rw------- 1 yhyjeon yhyjeon  288  1월  6 18:10 node3-peer-key.pem
-rw-rw-r-- 1 yhyjeon yhyjeon 1196  1월  6 18:10 node3-peer.pem

ETCD integration

When executing ETCD, set up https connection and certificate through environment variable file /etc/etcd/etcd.env or command line arguments. Only clients with certificates signed using the certificate authority (CA) certificates etcd-ca, etcd-ca-key that you created can access this ETCD instance.

$ vim /etc/etcd/etcd.env
#/etc/etcd/etcd.env
## Add the following to register the certificate authority and public and private keys of the certificates to be allowed.
## The located .pem certificate is a file that the user who will start the etcd process has read permission to read.
#Cert
ETCD_TRUSTED_CA_FILE=/etc/etcd/pki/etcd-ca.pem
ETCD_CERT_FILE=/etc/etcd/pki/node3.pem
ETCD_KEY_FILE=/etc/etcd/pki/node3-key.pem
ETCD_PEER_TRUSTED_CA_FILE=/etc/etcd/pki/etcd-ca.pem
ETCD_PEER_CERT_FILE=/etc/etcd/pki/node3-peer.pem
ETCD_PEER_KEY_FILE=/etc/etcd/pki/node3-peer-key.pem

Change ADVERTISE_CLIENT_URLS, LISTEN_CLIENT_URLS via command line arguments when running /etc/etcd/etcd.env file or ETCD

http://127.0.0.1:2379 is for use in a local environment and can be deleted if not needed.
The #Certs entry registers the certificates issued through the above process. The peer is utilized for the client and the rest for the server-side TLS certificates.
- ETCD_TRUSTED_CA_FILE : Path to the certificate authority (CA) certificate for the TLS certificate that the server will trust. If a valid certificate is configured, the ETCD server will validate the certificate for all clients. If you are utilizing client authentication without setting up a separate certificate authority, you should utilize the ETCD_CLIENT_CERT_AUTH=true option.
- ETCD_CERT_FILE : Path to the TLS certificate to be used for Client - Sever communication.
- ETCD_KEY_FILE : TLS Key path to be used for Client - Server communication.
- ETCD_PEER_TRUSTED_CA_FILE : Path to the certificate authority (CA) certificate of the TLS
  for ETCD peer-to-peer communication.
- ETCD_PEER_CERT_FILE : Path to the TLS certificate to be used for communication between ETCD
  peers.
- ETCD_PEER_KEY_FILE : TLS Key path to be used for communication between ETCD Peers.

#/etc/etcd/etcd.env
# ...
ETCD_ADVERTISE_CLIENT_URLS=https://172.18.0.2:2379
ETCD_LISTEN_CLIENT_URLS=https://172.18.0.2:2379,http://127.0.0.1:2379
# ...
#Certs
ETCD_TRUSTED_CA_FILE=/etc/etcd/pki/etcd-ca.pem
ETCD_CERT_FILE=/etc/etcd/pki/node1.pem
ETCD_KEY_FILE=/etc/etcd/pki/node1-key.pem
ETCD_PEER_TRUSTED_CA_FILE=/etc/etcd/pki/etcd-ca.pem
ETCD_PEER_CERT_FILE=/etc/etcd/pki/node1-peer.pem
ETCD_PEER_KEY_FILE=/etc/etcd/pki/node1-peer-key.pem

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Last updated 8 months ago

hashtagOverview

hashtagCreate a certificate

hashtagInstall the necessary tools

hashtagIssue a certificate

hashtag

hashtagETCD integration