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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright [yyyy] [name of copyright owner] 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # pihole-keepalived 2 | 3 | Simple failover configurations for a multi-pihole infrastructure. Tested on Raspbian Buster Lite, 2019-09 4 | 5 | The keepalived setup assumes that a non-responsive TCP query against port 53 on the peer indicates the peer is down. At present, this failover configuration does not address issues at the DNS application layer. 6 | 7 | TODO: Improve via DNS healthcheck script using UDP MISC_CHECK. Limited testing indicates this has CPU/perf implications, and further testing is required. 8 | 9 | ## Requirements 10 | 11 | 1. Two pihole instances installed and running. 12 | 2. Static IP assignment on both running pihole instances. 13 | 3. Only one pihole is configured to provide DHCP leases, or another device on the network is providing DHCP, such as a router or firewall. 14 | 15 | ## Static IP Assignment 16 | 17 | Plan for three static IP addresses in your network. 18 | 19 | 1. The main DNS VIP, maintained by keepalived 20 | 2. Primary pihole IP 21 | 3. Secondary pihole IP 22 | 23 | On your primary pihole, using your text editor of choice, ensure the following in /etc/dhcpcd.conf, adjusting the IP address: 24 | 25 | ``` 26 | interface eth0 27 | static ip_address=192.168.0.101/24 28 | static routers=192.168.0.1 29 | static domain_name_servers=192.168.0.100 192.168.0.101 192.168.0.102 30 | ``` 31 | 32 | Save the file and either restart or run `systemctl restart dhcpcd`. 33 | 34 | Repeat the above steps on your secondary pihole, adjusting IP addresses as necessary. 35 | 36 | 37 | ## Custom DHCP config 38 | 39 | If one of the pihole is providing DHCP leases, to ensure that DHCP clients can properly utilize the keepalived DNS VIP, set the following in `/etc/dnsmasq.d/99-custom.conf`, creating the file if necessary: 40 | 41 | ``` 42 | dhcp-option=6,192.168.1.100,192.168.1.101,192.168.1.102 43 | ``` 44 | 45 | Restart dnsmasq via `sudo pihole restartdns`. 46 | 47 | 48 | ## Keepalived setup, primary pihole 49 | 50 | 1. Install keepalived. 51 | 52 | ``` 53 | sudo apt-get update && sudo apt-get install keepalived 54 | ``` 55 | 56 | 2. Create the keepalived configuration at /etc/keepalived/keepalived.conf below. 57 | 58 | ``` 59 | vrrp_instance pihole { 60 | interface eth0 61 | state BACKUP 62 | virtual_router_id 100 63 | priority 100 64 | authentication { 65 | auth_type PASS 66 | auth_pass s0me_random_p@ssw0rd 67 | } 68 | virtual_ipaddress { 69 | 192.168.0.100/24 dev eth0 70 | } 71 | } 72 | 73 | # Check for TCP 74 | virtual_server 192.168.0.100 53 { 75 | delay_loop 6 76 | lb_algo wlc 77 | protocol TCP 78 | 79 | real_server 192.168.0.101 53 { 80 | weight 100 81 | TCP_CHECK { 82 | connect_timeout 6 83 | } 84 | } 85 | 86 | real_server 192.168.0.102 53 { 87 | weight 100 88 | TCP_CHECK { 89 | connect_timeout 6 90 | } 91 | } 92 | } 93 | ``` 94 | 95 | 3. Start and enable keepalived 96 | 97 | ``` 98 | systemctl --now enable keepalived 99 | ``` 100 | 101 | 4. Validate primary pihole 102 | 103 | Ensure no errors in keepalived journal messages 104 | 105 | ``` 106 | journalctl -u keepalived 107 | ``` 108 | 109 | Validate the new VIP 192.168.0.100 VIP exists on eth0 110 | 111 | ``` 112 | ip a s eth0 113 | ``` 114 | 115 | Attempt to resolve DNS against the VIP 116 | 117 | ``` 118 | dig @192.168.0.100 duckduckgo.com 119 | dig +notcp @192.168.0.100 duckduckgo.com 120 | ``` 121 | 122 | ## Keepalived Setup, secondary pihole 123 | 124 | On 192.168.0.102, perform steps 1 (install keepalived) and 2 (configure keepalived), using the following configuration. Take note of the different: `priority` values. The router ID references the last octet of the VIP and needs to be internally consistent between all peers. The priority on the secondary must be _lower_ than the primary. 125 | 126 | ``` 127 | vrrp_instance pihole { 128 | interface eth0 129 | state BACKUP 130 | virtual_router_id 100 131 | priority 99 132 | authentication { 133 | auth_type PASS 134 | auth_pass s0me_random_p@ssw0rd 135 | } 136 | virtual_ipaddress { 137 | 192.168.0.100/24 dev eth0 138 | } 139 | } 140 | 141 | # Check for TCP 142 | virtual_server 192.168.0.100 53 { 143 | delay_loop 6 144 | lb_algo wlc 145 | protocol TCP 146 | 147 | real_server 192.168.0.101 53 { 148 | weight 100 149 | TCP_CHECK { 150 | connect_timeout 6 151 | } 152 | } 153 | 154 | real_server 192.168.0.102 53 { 155 | weight 100 156 | TCP_CHECK { 157 | connect_timeout 6 158 | } 159 | } 160 | } 161 | ``` 162 | 163 | Repeat steps 3 and 4 from the primary keepalived config above, keeping in mind that the VIP should _not_ appear on the secondary pihole. 164 | 165 | Test failover by shutting down the primary pihole and validating that the keepalived VIP appears on the secondary. 166 | -------------------------------------------------------------------------------- /etc/dnsmasq.d/99-custom.conf: -------------------------------------------------------------------------------- 1 | dhcp-option=6,192.168.0.100,192.168.0.101,192.168.0.102 2 | -------------------------------------------------------------------------------- /etc/keepalived/keepalived.conf: -------------------------------------------------------------------------------- 1 | # primary pihole keepalived 2 | 3 | vrrp_instance pihole { 4 | interface eth0 5 | state BACKUP 6 | virtual_router_id 100 7 | priority 100 8 | authentication { 9 | auth_type PASS 10 | auth_pass s0me_random_p@ssw0rd 11 | } 12 | virtual_ipaddress { 13 | 192.168.0.100/24 dev eth0 14 | } 15 | } 16 | 17 | # Check for TCP 18 | virtual_server 192.168.0.100 53 { 19 | delay_loop 6 20 | lb_algo wlc 21 | protocol TCP 22 | 23 | real_server 192.168.0.101 53 { 24 | weight 100 25 | TCP_CHECK { 26 | connect_timeout 6 27 | } 28 | } 29 | 30 | real_server 192.168.0.102 53 { 31 | weight 100 32 | TCP_CHECK { 33 | connect_timeout 6 34 | } 35 | } 36 | } 37 | --------------------------------------------------------------------------------