Set Valkey memory and eviction defaults (#9602)

Author: pshankinclarke

install/valkey-install.sh

@@ -17,10 +17,22 @@ msg_info "Installing Valkey"
 $STD apt update
 $STD apt install -y valkey openssl
 sed -i 's/^bind .*/bind 0.0.0.0/' /etc/valkey/valkey.conf
+
 PASS="$(openssl rand -base64 48 | tr -dc 'a-zA-Z0-9' | head -c32)"
 echo "requirepass $PASS" >> /etc/valkey/valkey.conf
 echo "$PASS" >~/valkey.creds
 chmod 600 ~/valkey.creds
+
+MEMTOTAL_MB=$(free -m | grep ^Mem: | awk '{print $2}')
+# reserve 25% of a node type's maxmemory value for system use
+MAXMEMORY_MB=$((MEMTOTAL_MB * 75 / 100))
+
+echo "" >> /etc/valkey/valkey.conf
+echo "# Memory-optimized settings for small-scale deployments" >> /etc/valkey/valkey.conf
+echo "maxmemory ${MAXMEMORY_MB}mb" >> /etc/valkey/valkey.conf
+echo "maxmemory-policy allkeys-lru" >> /etc/valkey/valkey.conf
+echo "maxmemory-samples 10" >> /etc/valkey/valkey.conf
+
 systemctl enable -q --now valkey-server
 systemctl restart valkey-server
 msg_ok "Installed Valkey"