Redis

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This is most about AWS ElastiCache service, Redis cache that is fast key/value store.


Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache and message broker. It supports data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs, geospatial indexes with radius queries and streams. Read more...


Install

Install the cli client only 

# Local laptop
## Version distributed with Ubuntu 20.04
apt install redis-tools # redis-cli 5.0.7, does not support redis-over-TLS --tls flag

## Latest release, eg. redis-cli 6.2.3. supports redis-over-TLS --tls flag
add-apt-repository ppa:redislabs/redis
apt-get install redis


# A pod
kubectl -n default run --image=ubuntu:20.04 ubuntu-1 --rm -it -- bash
export DEBIAN_FRONTEND=noninteractive
apt update; apt install -yqq dnsutils netcat stunnel vim net-tools # select 8, 27, these are optional packages
apt install -yqq redis-tools # redis-cli 5.0.7

## Latest release, eg. redis-cli 6.2.3
apt-get install software-properties-common # installs 'add-apt-repository'
add-apt-repository ppa:redislabs/redis
apt-get install redis


Test connectivity 

REDIS_PRIMARY=master.re111111111111.aaaaaa.ng.0001.aaa.cache.amazonaws.com
REDIS_REPLICA=replica.re111111111111.aaaaaa.ng.0001.aaa.cache.amazonaws.com
REDIS_AUTH_TOKEN='p#ssw0rd1'

redis-cli -h $REDIS_PRIMARY -p 6379 ping # no-encription-in-transit
PONG

Connect to the server and run commands from cli

Note: All below examples are based on connecting to AWS Redis ElasticCache

No-auth, no-encryption-in-transit

# connect to the server cli
$ redis-cli -h redis.acme.com -p 6379

# Using docker
$ docker run -it redis redis-cli -h redis.acme.com -p 6379

# Using telnet `apt install telnet`
telnet redis.acme.com 6379
Trying 10.10.10.111... # <-- server IP
Connected to redis.acme.com.
Escape character is '^]'.
monitor                     # command 1, streams back every command processed by Redis
+OK                         # stop monitoring by Ctl^C or issue command `QUIT` if using Telnet session
QUIT
+OK
Connection closed by foreign host.

telnet redis.acme.com 6379
Trying 10.10.10.111... # <-- server IP
KEYS AuthenticationService  # command 2, show keys
+1600340814.733253 [0 10.10.10.222:59730] "keys" "AuthenticationService" # <-- .222 client IP
*0
^]
telnet> Connection closed.

Auth and encryption-in-transit

Stunnel proxy

Note: If your redis-cli <6.x use this method


Authenticating Users with the Redis AUTH Command, with encryption in transport and at rest. This requires to use some sort of proxy that will enable SSL transport in beetween the redis-client and the AWS hosted redis-cache. 

apt update; apt install -yqq dnsutils netcat redis-tools stunnel vim net-tools procps iproute2
# | iproute2(ss), procps(ps), dnsutils(dig)

# Config vars
 STUNNEL_UID=root
STUNNEL_GUID=root
PORT_PRIMARY=6379
PORT_REPLICA=6380
REDIS_PRIMARY=master.re111111111111.aaaaaa.ng.0001.aaa.cache.amazonaws.com
REDIS_REPLICA=replica.re111111111111.aaaaaa.ng.0001.aaa.cache.amazonaws.com

# Config 'stunnel' - local laptop
sudo bash -c "cat > /etc/stunnel/redis-cli.conf << EOF
fips = no
setuid = $STUNNEL_UID
setgid = $STUNNEL_GUID
pid = /var/run/stunnel.pid
debug = 7
delay = yes
#options = NO_SSLv2 # these options might be not valid anymore
#options = NO_SSLv3
[redis-cli]
   client = yes
   accept = 127.0.0.1:${PORT_PRIMARY}
   connect = $REDIS_PRIMARY:6379
[redis-cli-replica]
   client = yes
   accept = 127.0.0.1:${PORT_REPLICA}
   connect = $REDIS_REPLICA:6379
EOF"
cat /etc/stunnel/redis-cli.conf

# Config 'stunnel' - container (works with Istio sidecar, no-privilege mode needed)
cat > /etc/stunnel/redis-cli.conf << EOF
fips = no
setuid = $STUNNEL_UID
setgid = $STUNNEL_GUID
pid = /var/run/stunnel.pid
debug = 7
delay = yes
#options = NO_SSLv2 # Illegal TLS option
options = NO_SSLv3
[redis-cli]
   client = yes
   accept = 127.0.0.1:${PORT_PRIMARY}
   connect = $REDIS_PRIMARY:6379
[redis-cli-replica]
   client = yes
   accept = 127.0.0.1:${PORT_REPLICA}
   connect = $REDIS_REPLICA:6379
EOF
cat /etc/stunnel/redis-cli.conf


Create proxy-tunnel 

stunnel /etc/stunnel/redis-cli.conf
netstat -tulnp | grep -i stunnel
root@ubuntu-1-57789d9bf7-pmg2j:/# netstat -tulnp | grep -i stunnel
tcp        0      0 127.0.0.1:6379          0.0.0.0:*               LISTEN      1049/stunnel
tcp        0      0 127.0.0.1:6380          0.0.0.0:*               LISTEN      1049/stunnel

pkill stunnel # kill stunnel

# Connect
redis-cli -h localhost      -p $PORT_PRIMARY
redis-cli -h localhost      -p $PORT_PRIMARY -a "$REDIS_AUTH_TOKEN"
redis-cli -h localhost      -p $PORT_PRIMARY -a "$REDIS_AUTH_TOKEN" ping
redis-cli -h localhost      -p $PORT_PRIMARY -a "$REDIS_AUTH_TOKEN" info server
redis-cli -h $REDIS_PRIMARY -p $PORT_PRIMARY -a "$REDIS_AUTH_TOKEN" --stat
redis-cli -u redis://"${REDIS_AUTH_TOKEN}"@${REDIS_PRIMARY}:${PORT_PRIMARY}/0 ping # never worked, could password contain unallowed chars


Note: Auth redis-cli -h localhost -p 8000 -a password, alternatively, you can authenticate by running the auth command followed by your password after establishing the connection: auth password1


Note: Continuous stats mode redis-cli --stat -i 5, in this mode a new line is printed every second with useful information and the difference between the old data point, -i 5 emits lines every 5 seconds, default is 1s

redis-cli --tls (6.x)

REDIS_PRIMARY=master.re111111111111.aaaaaa.ng.0001.aaa.cache.amazonaws.com
REDIS_REPLICA=replica.re111111111111.aaaaaa.ng.0001.aaa.cache.amazonaws.com
REDIS_AUTH_TOKEN='passwprd1' # default env var is: REDISCLI_AUTH

# connects to a cluster with [x]encryption enabled
redis-cli -h $REDIS_PRIMARY -p 6379 --no-auth-warning --tls
# connects to a cluster with [x]encryption and [x]authentication enabled
redis-cli -h $REDIS_PRIMARY -p 6379 --no-auth-warning --tls -a $REDIS_AUTH_TOKEN --verbose

# if using cname eg. REDIS_PRIMARY=redis then --sni is required
redis-cli -h $REDIS_PRIMARY -p 6379 --no-auth-warning --tls -a $REDIS_AUTH_TOKEN --sni $REDIS_PRIMARY --verbose


Verify RedisCache SSL 

openssl s_client -host [endpoint name] -port [endpoint port number] -cert redislabs_user.crt -key redislabs_user_private.key -CAfile redislabs_ca.pem -crlf

Running the command will produce a long sequence of output about various aspects of the TLS connection with a message at the end that looks like: Verify return code: 0 (ok), any other return code or message, the connection wasn’t able to establish securely.

Redis server

Convenient sample tls certs used here can be found: OpenVPN/openvpn - sample-keys. Redis-server implementation can use public/private certificates. The private part (server) and public part the (client). When using the redis-client, the public part of the certificates is expected instead of the private one. 

curl -sLO https://raw.githubusercontent.com/OpenVPN/openvpn/master/sample/sample-keys/ca.crt
curl -sLO https://raw.githubusercontent.com/OpenVPN/openvpn/master/sample/sample-keys/server.crt
curl -sLO https://raw.githubusercontent.com/OpenVPN/openvpn/master/sample/sample-keys/server.key
curl -sLO https://raw.githubusercontent.com/OpenVPN/openvpn/master/sample/sample-keys/client.crt
curl -sLO https://raw.githubusercontent.com/OpenVPN/openvpn/master/sample/sample-keys/client.key

kubectl create secret generic redis-tls --from-file ca.crt --from-file server.key --from-file server.crt

cat <<EOF >values.yaml
cluster:
  enabled: false

tls:
  enabled: true
  authClients: true
  certificatesSecret: redis-tls
  certFilename: server.crt
  certKeyFilename: server.key
  certCAFilename: ca.crt

master:
  readinessProbe:
    enabled: false
  livenessProbe:
    enabled: false
EOF

helm install redis bitnami/redis -f values.yaml

export REDIS_PASSWORD=$(kubectl get secret --namespace default redis -o jsonpath="{.data.redis-password}" | base64 --decode)
kubectl run redis-client --restart='Never' --env REDIS_PASSWORD=$REDIS_PASSWORD --image docker.io/bitnami/redis:6.0.6-debian-10-r10 --command -- sleep infinity
kubectl cp --namespace default client.crt redis-client:/tmp/client.crt
kubectl cp --namespace default client.key redis-client:/tmp/client.key
kubectl cp --namespace default ca.crt redis-client:/tmp/ca.crt

kubectl exec -ti redis-client -- redis-cli -h redis-master -a $REDIS_PASSWORD --tls --cert /tmp/client.crt --key /tmp/client.key --cacert /tmp/ca.crt

Note: This should be not necessary in a near feature. Note that in the values.yaml, the readiness and liveness probes are disabled to avoid the master pod being restarted when enabling client authentication.

Commands

# auth
redis.acme.com:6379> AUTH p!ssw0rd1

# list who is connected
localhost:6379> CLIENT LIST
id=136260 addr=10.0.0.5:42257 fd=9 name=backendservice-11111f57fc-h7l9b age=96965 idle=49 flags=P db=0 sub=1 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=ping
id=136261 addr=10.0.0.5:46525 fd=10 name=backendservice-11111f57fc-h7l9b age=96965 idle=6 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=evalsha
id=138125 addr=10.0.0.5:56729 fd=20 name=authservice-2222265797-zkcnw age=42695 idle=22 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=info
id=138126 addr=10.0.0.5:48548 fd=26 name=authservice-2222265797-zkcnw age=42694 idle=22 flags=P db=0 sub=1 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=ping

# list keys 'KEYS pattern'
redis.acme.com:6379> KEYS *Auth*

# set value
redis.acme.com:6379>  SET mykey 10
"OK"

# read value
redis.acme.com:6379>  DUMP mykey
"\u0000\xC0\n\t\u0000\xBEm\u0006\x89Z(\u0000\n"

# monitor activity
redis.acme.com:6379>  MONITOR
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