How to Debug and Fix Uncaught Redis ConnectionException leading to cascading API downtime in Modern Magento 2 Applications

Diagnosing the Root Cause: Uncaught Redis ConnectionException

The dreaded Predis\Connection\ConnectionException in a Magento 2 application, especially when it cascades into API downtime, is a critical issue demanding immediate and precise diagnosis. This exception typically surfaces when the Magento application, or more specifically, its caching or session management layers, fails to establish or maintain a connection with the Redis server. In a high-traffic e-commerce environment, this can cripple the entire system, from frontend page loads to backend API operations.

The most common culprits are network issues, Redis server unavailability, incorrect connection credentials, or resource exhaustion on the Redis server itself. Let’s start by examining the Magento application logs for detailed error messages.

Log Analysis and Initial Checks

Magento’s exception logs are the first line of defense. Navigate to var/log/exception.log and var/log/system.log on your Magento installation. Look for entries timestamped around the time of the reported downtime. The exception.log will likely contain the full stack trace of the Predis\Connection\ConnectionException.

A typical log entry might look like this:

[2023-10-27 10:30:05] main.CRITICAL: Predis\Connection\ConnectionException: Connection refused [tcp://127.0.0.1:6379] in /var/www/html/vendor/predis/predis/src/Connection/AbstractConnection.php:155
Stack trace:
#0 /var/www/html/vendor/predis/predis/src/Connection/StreamConnection.php(107): Predis\Connection\AbstractConnection->onConnectionError('Connection refu...', 111)
#1 /var/www/html/vendor/predis/predis/src/Connection/StreamConnection.php(148): Predis\Connection\StreamConnection->connect()
#2 /var/www/html/vendor/predis/predis/src/Client.php(366): Predis\Connection\StreamConnection->write('PING\r\n')
#3 /var/www/html/vendor/magento/framework/ belakang/Redis/ConnectionFactory.php(77): Predis\Client->__call('ping', Array)
#4 /var/www/html/vendor/magento/framework/ belakang/Redis/CacheFrontend.php(126): Magento\Framework\ belakang\Redis\ConnectionFactory->create(Array)
#5 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend/Decorator/Logger.php(53): Magento\Framework\ belakang\Redis\CacheFrontend->getOption('master_server')
#6 /var/www/html/vendor/magento/framework/ belakang/Cache.php(129): Magento\Framework\ belakang\Cache\Frontend\Decorator\Logger->test()
#7 /var/www/html/app/code/Magento/PageCache/Model/Cache.php(112): Magento\Framework\ belakang\Cache->test()
#8 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\PageCache\Model\Cache->test()
#9 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#10 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#11 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#12 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#13 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#14 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#15 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#16 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#17 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#18 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#19 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#20 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#21 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#22 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#23 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#24 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#25 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#26 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#27 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#28 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#29 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#30 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#31 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#32 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#33 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#34 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#35 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#36 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#37 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#38 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#39 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#40 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#41 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#42 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#43 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#44 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#45 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#46 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#47 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#48 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#49 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#50 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#51 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#52 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#53 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#54 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#55 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#56 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#57 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#58 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#59 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#60 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#61 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#62 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#63 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#64 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#65 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#66 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#67 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#68 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#69 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#70 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#71 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#72 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#73 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#74 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#75 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#76 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#77 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#78 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#79 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#80 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#81 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#82 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#83 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#84 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#85 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#86 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#87 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#88 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#89 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#90 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#91 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#92 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#93 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#94 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#95 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#96 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#97 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#98 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#99 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#100 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#101 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#102 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#103 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#104 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#105 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#106 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#107 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#108 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#109 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#110 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#111 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#112 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#113 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#114 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#115 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#116 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#117 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#118 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#119 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#120 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#121 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#122 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#123 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#124 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#125 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#126 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#127 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#128 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#129 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#130 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#131 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#132 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#133 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#134 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#135 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#136 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#137 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#138 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#139 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#140 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#141 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#142 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#143 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#144 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#145 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#146 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#147 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#148 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#149 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#150 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#151 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#152 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#153 /var/www/html/vendor/magento/framework/ belakang/Cache/Frontend.php(231): Magento\Framework\ belakang\Cache\Frontend->getOption('master_server')
#154 /var