Install redis on the database server

Antonio Terceiro
1 parent 341821af
Showing 4 changed files with 788 additions and 0 deletions Show diff stats
config/roles/database_server.rb
cookbooks/redis/recipes/default.rb
cookbooks/redis/templates/redis.conf.erb
test/redis_test.sh
@@ -2,6 +2,7 @@ name &#39;database_server&#39;
 description 'Database server'
 run_list *[
   'recipe[postgresql]',
+  'recipe[redis]',
   'recipe[postgresql::colab]',
   'recipe[postgresql::gitlab]',
 ]
@@ -0,0 +1,13 @@
+package 'redis'
+
+template '/etc/redis.conf' do
+  user 'root'
+  group 'root'
+  mode 0644
+
+  notifies :restart, 'service[redis]'
+end
+
+service 'redis' do
+  action [:enable, :start]
+end
@@ -0,0 +1,763 @@
+# MANAGED WITH CHEF. DO NOT MAKE MANUAL CHANGES
+
+# Redis configuration file example
+
+# Note on units: when memory size is needed, it is possible to specify
+# it in the usual form of 1k 5GB 4M and so forth:
+#
+# 1k => 1000 bytes
+# 1kb => 1024 bytes
+# 1m => 1000000 bytes
+# 1mb => 1024*1024 bytes
+# 1g => 1000000000 bytes
+# 1gb => 1024*1024*1024 bytes
+#
+# units are case insensitive so 1GB 1Gb 1gB are all the same.
+
+################################## INCLUDES ###################################
+
+# Include one or more other config files here.  This is useful if you
+# have a standard template that goes to all Redis server but also need
+# to customize a few per-server settings.  Include files can include
+# other files, so use this wisely.
+#
+# Notice option "include" won't be rewritten by command "CONFIG REWRITE"
+# from admin or Redis Sentinel. Since Redis always uses the last processed
+# line as value of a configuration directive, you'd better put includes
+# at the beginning of this file to avoid overwriting config change at runtime.
+#
+# If instead you are interested in using includes to override configuration
+# options, it is better to use include as the last line.
+#
+# include /path/to/local.conf
+# include /path/to/other.conf
+
+################################ GENERAL  #####################################
+
+# By default Redis does not run as a daemon. Use 'yes' if you need it.
+# Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
+daemonize no
+
+# When running daemonized, Redis writes a pid file in /var/run/redis.pid by
+# default. You can specify a custom pid file location here.
+pidfile /var/run/redis/redis.pid
+
+# Accept connections on the specified port, default is 6379.
+# If port 0 is specified Redis will not listen on a TCP socket.
+port 6379
+
+# TCP listen() backlog.
+#
+# In high requests-per-second environments you need an high backlog in order
+# to avoid slow clients connections issues. Note that the Linux kernel
+# will silently truncate it to the value of /proc/sys/net/core/somaxconn so
+# make sure to raise both the value of somaxconn and tcp_max_syn_backlog
+# in order to get the desired effect.
+tcp-backlog 511
+
+# By default Redis listens for connections from all the network interfaces
+# available on the server. It is possible to listen to just one or multiple
+# interfaces using the "bind" configuration directive, followed by one or
+# more IP addresses.
+#
+# Examples:
+#
+# bind 192.168.1.100 10.0.0.1
+bind 127.0.0.1 <%= node['peers']['database'] %>
+
+# Specify the path for the Unix socket that will be used to listen for
+# incoming connections. There is no default, so Redis will not listen
+# on a unix socket when not specified.
+#
+# unixsocket /tmp/redis.sock
+# unixsocketperm 700
+
+# Close the connection after a client is idle for N seconds (0 to disable)
+timeout 0
+
+# TCP keepalive.
+#
+# If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence
+# of communication. This is useful for two reasons:
+#
+# 1) Detect dead peers.
+# 2) Take the connection alive from the point of view of network
+#    equipment in the middle.
+#
+# On Linux, the specified value (in seconds) is the period used to send ACKs.
+# Note that to close the connection the double of the time is needed.
+# On other kernels the period depends on the kernel configuration.
+#
+# A reasonable value for this option is 60 seconds.
+tcp-keepalive 0
+
+# Specify the server verbosity level.
+# This can be one of:
+# debug (a lot of information, useful for development/testing)
+# verbose (many rarely useful info, but not a mess like the debug level)
+# notice (moderately verbose, what you want in production probably)
+# warning (only very important / critical messages are logged)
+loglevel notice
+
+# Specify the log file name. Also the empty string can be used to force
+# Redis to log on the standard output. Note that if you use standard
+# output for logging but daemonize, logs will be sent to /dev/null
+logfile /var/log/redis/redis.log
+
+# To enable logging to the system logger, just set 'syslog-enabled' to yes,
+# and optionally update the other syslog parameters to suit your needs.
+# syslog-enabled no
+
+# Specify the syslog identity.
+# syslog-ident redis
+
+# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
+# syslog-facility local0
+
+# Set the number of databases. The default database is DB 0, you can select
+# a different one on a per-connection basis using SELECT <dbid> where
+# dbid is a number between 0 and 'databases'-1
+databases 16
+
+################################ SNAPSHOTTING  ################################
+#
+# Save the DB on disk:
+#
+#   save <seconds> <changes>
+#
+#   Will save the DB if both the given number of seconds and the given
+#   number of write operations against the DB occurred.
+#
+#   In the example below the behaviour will be to save:
+#   after 900 sec (15 min) if at least 1 key changed
+#   after 300 sec (5 min) if at least 10 keys changed
+#   after 60 sec if at least 10000 keys changed
+#
+#   Note: you can disable saving at all commenting all the "save" lines.
+#
+#   It is also possible to remove all the previously configured save
+#   points by adding a save directive with a single empty string argument
+#   like in the following example:
+#
+#   save ""
+
+save 900 1
+save 300 10
+save 60 10000
+
+# By default Redis will stop accepting writes if RDB snapshots are enabled
+# (at least one save point) and the latest background save failed.
+# This will make the user aware (in a hard way) that data is not persisting
+# on disk properly, otherwise chances are that no one will notice and some
+# disaster will happen.
+#
+# If the background saving process will start working again Redis will
+# automatically allow writes again.
+#
+# However if you have setup your proper monitoring of the Redis server
+# and persistence, you may want to disable this feature so that Redis will
+# continue to work as usual even if there are problems with disk,
+# permissions, and so forth.
+stop-writes-on-bgsave-error yes
+
+# Compress string objects using LZF when dump .rdb databases?
+# For default that's set to 'yes' as it's almost always a win.
+# If you want to save some CPU in the saving child set it to 'no' but
+# the dataset will likely be bigger if you have compressible values or keys.
+rdbcompression yes
+
+# Since version 5 of RDB a CRC64 checksum is placed at the end of the file.
+# This makes the format more resistant to corruption but there is a performance
+# hit to pay (around 10%) when saving and loading RDB files, so you can disable it
+# for maximum performances.
+#
+# RDB files created with checksum disabled have a checksum of zero that will
+# tell the loading code to skip the check.
+rdbchecksum yes
+
+# The filename where to dump the DB
+dbfilename dump.rdb
+
+# The working directory.
+#
+# The DB will be written inside this directory, with the filename specified
+# above using the 'dbfilename' configuration directive.
+# 
+# The Append Only File will also be created inside this directory.
+# 
+# Note that you must specify a directory here, not a file name.
+dir /var/lib/redis/
+
+################################# REPLICATION #################################
+
+# Master-Slave replication. Use slaveof to make a Redis instance a copy of
+# another Redis server. A few things to understand ASAP about Redis replication.
+#
+# 1) Redis replication is asynchronous, but you can configure a master to
+#    stop accepting writes if it appears to be not connected with at least
+#    a given number of slaves.
+# 2) Redis slaves are able to perform a partial resynchronization with the
+#    master if the replication link is lost for a relatively small amount of
+#    time. You may want to configure the replication backlog size (see the next
+#    sections of this file) with a sensible value depending on your needs.
+# 3) Replication is automatic and does not need user intervention. After a
+#    network partition slaves automatically try to reconnect to masters
+#    and resynchronize with them.
+#
+# slaveof <masterip> <masterport>
+
+# If the master is password protected (using the "requirepass" configuration
+# directive below) it is possible to tell the slave to authenticate before
+# starting the replication synchronization process, otherwise the master will
+# refuse the slave request.
+#
+# masterauth <master-password>
+
+# When a slave loses its connection with the master, or when the replication
+# is still in progress, the slave can act in two different ways:
+#
+# 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will
+#    still reply to client requests, possibly with out of date data, or the
+#    data set may just be empty if this is the first synchronization.
+#
+# 2) if slave-serve-stale-data is set to 'no' the slave will reply with
+#    an error "SYNC with master in progress" to all the kind of commands
+#    but to INFO and SLAVEOF.
+#
+slave-serve-stale-data yes
+
+# You can configure a slave instance to accept writes or not. Writing against
+# a slave instance may be useful to store some ephemeral data (because data
+# written on a slave will be easily deleted after resync with the master) but
+# may also cause problems if clients are writing to it because of a
+# misconfiguration.
+#
+# Since Redis 2.6 by default slaves are read-only.
+#
+# Note: read only slaves are not designed to be exposed to untrusted clients
+# on the internet. It's just a protection layer against misuse of the instance.
+# Still a read only slave exports by default all the administrative commands
+# such as CONFIG, DEBUG, and so forth. To a limited extent you can improve
+# security of read only slaves using 'rename-command' to shadow all the
+# administrative / dangerous commands.
+slave-read-only yes
+
+# Slaves send PINGs to server in a predefined interval. It's possible to change
+# this interval with the repl_ping_slave_period option. The default value is 10
+# seconds.
+#
+# repl-ping-slave-period 10
+
+# The following option sets the replication timeout for:
+#
+# 1) Bulk transfer I/O during SYNC, from the point of view of slave.
+# 2) Master timeout from the point of view of slaves (data, pings).
+# 3) Slave timeout from the point of view of masters (REPLCONF ACK pings).
+#
+# It is important to make sure that this value is greater than the value
+# specified for repl-ping-slave-period otherwise a timeout will be detected
+# every time there is low traffic between the master and the slave.
+#
+# repl-timeout 60
+
+# Disable TCP_NODELAY on the slave socket after SYNC?
+#
+# If you select "yes" Redis will use a smaller number of TCP packets and
+# less bandwidth to send data to slaves. But this can add a delay for
+# the data to appear on the slave side, up to 40 milliseconds with
+# Linux kernels using a default configuration.
+#
+# If you select "no" the delay for data to appear on the slave side will
+# be reduced but more bandwidth will be used for replication.
+#
+# By default we optimize for low latency, but in very high traffic conditions
+# or when the master and slaves are many hops away, turning this to "yes" may
+# be a good idea.
+repl-disable-tcp-nodelay no
+
+# Set the replication backlog size. The backlog is a buffer that accumulates
+# slave data when slaves are disconnected for some time, so that when a slave
+# wants to reconnect again, often a full resync is not needed, but a partial
+# resync is enough, just passing the portion of data the slave missed while
+# disconnected.
+#
+# The biggest the replication backlog, the longer the time the slave can be
+# disconnected and later be able to perform a partial resynchronization.
+#
+# The backlog is only allocated once there is at least a slave connected.
+#
+# repl-backlog-size 1mb
+
+# After a master has no longer connected slaves for some time, the backlog
+# will be freed. The following option configures the amount of seconds that
+# need to elapse, starting from the time the last slave disconnected, for
+# the backlog buffer to be freed.
+#
+# A value of 0 means to never release the backlog.
+#
+# repl-backlog-ttl 3600
+
+# The slave priority is an integer number published by Redis in the INFO output.
+# It is used by Redis Sentinel in order to select a slave to promote into a
+# master if the master is no longer working correctly.
+#
+# A slave with a low priority number is considered better for promotion, so
+# for instance if there are three slaves with priority 10, 100, 25 Sentinel will
+# pick the one with priority 10, that is the lowest.
+#
+# However a special priority of 0 marks the slave as not able to perform the
+# role of master, so a slave with priority of 0 will never be selected by
+# Redis Sentinel for promotion.
+#
+# By default the priority is 100.
+slave-priority 100
+
+# It is possible for a master to stop accepting writes if there are less than
+# N slaves connected, having a lag less or equal than M seconds.
+#
+# The N slaves need to be in "online" state.
+#
+# The lag in seconds, that must be <= the specified value, is calculated from
+# the last ping received from the slave, that is usually sent every second.
+#
+# This option does not GUARANTEES that N replicas will accept the write, but
+# will limit the window of exposure for lost writes in case not enough slaves
+# are available, to the specified number of seconds.
+#
+# For example to require at least 3 slaves with a lag <= 10 seconds use:
+#
+# min-slaves-to-write 3
+# min-slaves-max-lag 10
+#
+# Setting one or the other to 0 disables the feature.
+#
+# By default min-slaves-to-write is set to 0 (feature disabled) and
+# min-slaves-max-lag is set to 10.
+
+################################## SECURITY ###################################
+
+# Require clients to issue AUTH <PASSWORD> before processing any other
+# commands.  This might be useful in environments in which you do not trust
+# others with access to the host running redis-server.
+#
+# This should stay commented out for backward compatibility and because most
+# people do not need auth (e.g. they run their own servers).
+# 
+# Warning: since Redis is pretty fast an outside user can try up to
+# 150k passwords per second against a good box. This means that you should
+# use a very strong password otherwise it will be very easy to break.
+#
+# requirepass foobared
+
+# Command renaming.
+#
+# It is possible to change the name of dangerous commands in a shared
+# environment. For instance the CONFIG command may be renamed into something
+# hard to guess so that it will still be available for internal-use tools
+# but not available for general clients.
+#
+# Example:
+#
+# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
+#
+# It is also possible to completely kill a command by renaming it into
+# an empty string:
+#
+# rename-command CONFIG ""
+#
+# Please note that changing the name of commands that are logged into the
+# AOF file or transmitted to slaves may cause problems.
+
+################################### LIMITS ####################################
+
+# Set the max number of connected clients at the same time. By default
+# this limit is set to 10000 clients, however if the Redis server is not
+# able to configure the process file limit to allow for the specified limit
+# the max number of allowed clients is set to the current file limit
+# minus 32 (as Redis reserves a few file descriptors for internal uses).
+#
+# Once the limit is reached Redis will close all the new connections sending
+# an error 'max number of clients reached'.
+#
+# maxclients 10000
+
+# Don't use more memory than the specified amount of bytes.
+# When the memory limit is reached Redis will try to remove keys
+# according to the eviction policy selected (see maxmemory-policy).
+#
+# If Redis can't remove keys according to the policy, or if the policy is
+# set to 'noeviction', Redis will start to reply with errors to commands
+# that would use more memory, like SET, LPUSH, and so on, and will continue
+# to reply to read-only commands like GET.
+#
+# This option is usually useful when using Redis as an LRU cache, or to set
+# a hard memory limit for an instance (using the 'noeviction' policy).
+#
+# WARNING: If you have slaves attached to an instance with maxmemory on,
+# the size of the output buffers needed to feed the slaves are subtracted
+# from the used memory count, so that network problems / resyncs will
+# not trigger a loop where keys are evicted, and in turn the output
+# buffer of slaves is full with DELs of keys evicted triggering the deletion
+# of more keys, and so forth until the database is completely emptied.
+#
+# In short... if you have slaves attached it is suggested that you set a lower
+# limit for maxmemory so that there is some free RAM on the system for slave
+# output buffers (but this is not needed if the policy is 'noeviction').
+#
+# maxmemory <bytes>
+
+# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
+# is reached. You can select among five behaviors:
+# 
+# volatile-lru -> remove the key with an expire set using an LRU algorithm
+# allkeys-lru -> remove any key accordingly to the LRU algorithm
+# volatile-random -> remove a random key with an expire set
+# allkeys-random -> remove a random key, any key
+# volatile-ttl -> remove the key with the nearest expire time (minor TTL)
+# noeviction -> don't expire at all, just return an error on write operations
+# 
+# Note: with any of the above policies, Redis will return an error on write
+#       operations, when there are not suitable keys for eviction.
+#
+#       At the date of writing this commands are: set setnx setex append
+#       incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
+#       sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
+#       zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
+#       getset mset msetnx exec sort
+#
+# The default is:
+#
+# maxmemory-policy volatile-lru
+
+# LRU and minimal TTL algorithms are not precise algorithms but approximated
+# algorithms (in order to save memory), so you can select as well the sample
+# size to check. For instance for default Redis will check three keys and
+# pick the one that was used less recently, you can change the sample size
+# using the following configuration directive.
+#
+# maxmemory-samples 3
+
+############################## APPEND ONLY MODE ###############################
+
+# By default Redis asynchronously dumps the dataset on disk. This mode is
+# good enough in many applications, but an issue with the Redis process or
+# a power outage may result into a few minutes of writes lost (depending on
+# the configured save points).
+#
+# The Append Only File is an alternative persistence mode that provides
+# much better durability. For instance using the default data fsync policy
+# (see later in the config file) Redis can lose just one second of writes in a
+# dramatic event like a server power outage, or a single write if something
+# wrong with the Redis process itself happens, but the operating system is
+# still running correctly.
+#
+# AOF and RDB persistence can be enabled at the same time without problems.
+# If the AOF is enabled on startup Redis will load the AOF, that is the file
+# with the better durability guarantees.
+#
+# Please check http://redis.io/topics/persistence for more information.
+
+appendonly no
+
+# The name of the append only file (default: "appendonly.aof")
+
+appendfilename "appendonly.aof"
+
+# The fsync() call tells the Operating System to actually write data on disk
+# instead to wait for more data in the output buffer. Some OS will really flush 
+# data on disk, some other OS will just try to do it ASAP.
+#
+# Redis supports three different modes:
+#
+# no: don't fsync, just let the OS flush the data when it wants. Faster.
+# always: fsync after every write to the append only log . Slow, Safest.
+# everysec: fsync only one time every second. Compromise.
+#
+# The default is "everysec", as that's usually the right compromise between
+# speed and data safety. It's up to you to understand if you can relax this to
+# "no" that will let the operating system flush the output buffer when
+# it wants, for better performances (but if you can live with the idea of
+# some data loss consider the default persistence mode that's snapshotting),
+# or on the contrary, use "always" that's very slow but a bit safer than
+# everysec.
+#
+# More details please check the following article:
+# http://antirez.com/post/redis-persistence-demystified.html
+#
+# If unsure, use "everysec".
+
+# appendfsync always
+appendfsync everysec
+# appendfsync no
+
+# When the AOF fsync policy is set to always or everysec, and a background
+# saving process (a background save or AOF log background rewriting) is
+# performing a lot of I/O against the disk, in some Linux configurations
+# Redis may block too long on the fsync() call. Note that there is no fix for
+# this currently, as even performing fsync in a different thread will block
+# our synchronous write(2) call.
+#
+# In order to mitigate this problem it's possible to use the following option
+# that will prevent fsync() from being called in the main process while a
+# BGSAVE or BGREWRITEAOF is in progress.
+#
+# This means that while another child is saving, the durability of Redis is
+# the same as "appendfsync none". In practical terms, this means that it is
+# possible to lose up to 30 seconds of log in the worst scenario (with the
+# default Linux settings).
+# 
+# If you have latency problems turn this to "yes". Otherwise leave it as
+# "no" that is the safest pick from the point of view of durability.
+
+no-appendfsync-on-rewrite no
+
+# Automatic rewrite of the append only file.
+# Redis is able to automatically rewrite the log file implicitly calling
+# BGREWRITEAOF when the AOF log size grows by the specified percentage.
+# 
+# This is how it works: Redis remembers the size of the AOF file after the
+# latest rewrite (if no rewrite has happened since the restart, the size of
+# the AOF at startup is used).
+#
+# This base size is compared to the current size. If the current size is
+# bigger than the specified percentage, the rewrite is triggered. Also
+# you need to specify a minimal size for the AOF file to be rewritten, this
+# is useful to avoid rewriting the AOF file even if the percentage increase
+# is reached but it is still pretty small.
+#
+# Specify a percentage of zero in order to disable the automatic AOF
+# rewrite feature.
+
+auto-aof-rewrite-percentage 100
+auto-aof-rewrite-min-size 64mb
+
+################################ LUA SCRIPTING  ###############################
+
+# Max execution time of a Lua script in milliseconds.
+#
+# If the maximum execution time is reached Redis will log that a script is
+# still in execution after the maximum allowed time and will start to
+# reply to queries with an error.
+#
+# When a long running script exceed the maximum execution time only the
+# SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be
+# used to stop a script that did not yet called write commands. The second
+# is the only way to shut down the server in the case a write commands was
+# already issue by the script but the user don't want to wait for the natural
+# termination of the script.
+#
+# Set it to 0 or a negative value for unlimited execution without warnings.
+lua-time-limit 5000
+
+################################## SLOW LOG ###################################
+
+# The Redis Slow Log is a system to log queries that exceeded a specified
+# execution time. The execution time does not include the I/O operations
+# like talking with the client, sending the reply and so forth,
+# but just the time needed to actually execute the command (this is the only
+# stage of command execution where the thread is blocked and can not serve
+# other requests in the meantime).
+# 
+# You can configure the slow log with two parameters: one tells Redis
+# what is the execution time, in microseconds, to exceed in order for the
+# command to get logged, and the other parameter is the length of the
+# slow log. When a new command is logged the oldest one is removed from the
+# queue of logged commands.
+
+# The following time is expressed in microseconds, so 1000000 is equivalent
+# to one second. Note that a negative number disables the slow log, while
+# a value of zero forces the logging of every command.
+slowlog-log-slower-than 10000
+
+# There is no limit to this length. Just be aware that it will consume memory.
+# You can reclaim memory used by the slow log with SLOWLOG RESET.
+slowlog-max-len 128
+
+################################ LATENCY MONITOR ##############################
+
+# The Redis latency monitoring subsystem samples different operations
+# at runtime in order to collect data related to possible sources of
+# latency of a Redis instance.
+#
+# Via the LATENCY command this information is available to the user that can
+# print graphs and obtain reports.
+#
+# The system only logs operations that were performed in a time equal or
+# greater than the amount of milliseconds specified via the
+# latency-monitor-threshold configuration directive. When its value is set
+# to zero, the latency monitor is turned off.
+#
+# By default latency monitoring is disabled since it is mostly not needed
+# if you don't have latency issues, and collecting data has a performance
+# impact, that while very small, can be measured under big load. Latency
+# monitoring can easily be enalbed at runtime using the command
+# "CONFIG SET latency-monitor-threshold <milliseconds>" if needed.
+latency-monitor-threshold 0
+
+############################# Event notification ##############################
+
+# Redis can notify Pub/Sub clients about events happening in the key space.
+# This feature is documented at http://redis.io/topics/notifications
+# 
+# For instance if keyspace events notification is enabled, and a client
+# performs a DEL operation on key "foo" stored in the Database 0, two
+# messages will be published via Pub/Sub:
+#
+# PUBLISH __keyspace@0__:foo del
+# PUBLISH __keyevent@0__:del foo
+#
+# It is possible to select the events that Redis will notify among a set
+# of classes. Every class is identified by a single character:
+#
+#  K     Keyspace events, published with __keyspace@<db>__ prefix.
+#  E     Keyevent events, published with __keyevent@<db>__ prefix.
+#  g     Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ...
+#  $     String commands
+#  l     List commands
+#  s     Set commands
+#  h     Hash commands
+#  z     Sorted set commands
+#  x     Expired events (events generated every time a key expires)
+#  e     Evicted events (events generated when a key is evicted for maxmemory)
+#  A     Alias for g$lshzxe, so that the "AKE" string means all the events.
+#
+#  The "notify-keyspace-events" takes as argument a string that is composed
+#  by zero or multiple characters. The empty string means that notifications
+#  are disabled at all.
+#
+#  Example: to enable list and generic events, from the point of view of the
+#           event name, use:
+#
+#  notify-keyspace-events Elg
+#
+#  Example 2: to get the stream of the expired keys subscribing to channel
+#             name __keyevent@0__:expired use:
+#
+#  notify-keyspace-events Ex
+#
+#  By default all notifications are disabled because most users don't need
+#  this feature and the feature has some overhead. Note that if you don't
+#  specify at least one of K or E, no events will be delivered.
+notify-keyspace-events ""
+
+############################### ADVANCED CONFIG ###############################
+
+# Hashes are encoded using a memory efficient data structure when they have a
+# small number of entries, and the biggest entry does not exceed a given
+# threshold. These thresholds can be configured using the following directives.
+hash-max-ziplist-entries 512
+hash-max-ziplist-value 64
+
+# Similarly to hashes, small lists are also encoded in a special way in order
+# to save a lot of space. The special representation is only used when
+# you are under the following limits:
+list-max-ziplist-entries 512
+list-max-ziplist-value 64
+
+# Sets have a special encoding in just one case: when a set is composed
+# of just strings that happens to be integers in radix 10 in the range
+# of 64 bit signed integers.
+# The following configuration setting sets the limit in the size of the
+# set in order to use this special memory saving encoding.
+set-max-intset-entries 512
+
+# Similarly to hashes and lists, sorted sets are also specially encoded in
+# order to save a lot of space. This encoding is only used when the length and
+# elements of a sorted set are below the following limits:
+zset-max-ziplist-entries 128
+zset-max-ziplist-value 64
+
+# HyperLogLog sparse representation bytes limit. The limit includes the
+# 16 bytes header. When an HyperLogLog using the sparse representation crosses
+# this limit, it is converted into the dense representation.
+#
+# A value greater than 16000 is totally useless, since at that point the
+# dense representation is more memory efficient.
+# 
+# The suggested value is ~ 3000 in order to have the benefits of
+# the space efficient encoding without slowing down too much PFADD,
+# which is O(N) with the sparse encoding. The value can be raised to
+# ~ 10000 when CPU is not a concern, but space is, and the data set is
+# composed of many HyperLogLogs with cardinality in the 0 - 15000 range.
+hll-sparse-max-bytes 3000
+
+# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
+# order to help rehashing the main Redis hash table (the one mapping top-level
+# keys to values). The hash table implementation Redis uses (see dict.c)
+# performs a lazy rehashing: the more operation you run into a hash table
+# that is rehashing, the more rehashing "steps" are performed, so if the
+# server is idle the rehashing is never complete and some more memory is used
+# by the hash table.
+# 
+# The default is to use this millisecond 10 times every second in order to
+# active rehashing the main dictionaries, freeing memory when possible.
+#
+# If unsure:
+# use "activerehashing no" if you have hard latency requirements and it is
+# not a good thing in your environment that Redis can reply form time to time
+# to queries with 2 milliseconds delay.
+#
+# use "activerehashing yes" if you don't have such hard requirements but
+# want to free memory asap when possible.
+activerehashing yes
+
+# The client output buffer limits can be used to force disconnection of clients
+# that are not reading data from the server fast enough for some reason (a
+# common reason is that a Pub/Sub client can't consume messages as fast as the
+# publisher can produce them).
+#
+# The limit can be set differently for the three different classes of clients:
+#
+# normal -> normal clients including MONITOR clients
+# slave  -> slave clients
+# pubsub -> clients subscribed to at least one pubsub channel or pattern
+#
+# The syntax of every client-output-buffer-limit directive is the following:
+#
+# client-output-buffer-limit <class> <hard limit> <soft limit> <soft seconds>
+#
+# A client is immediately disconnected once the hard limit is reached, or if
+# the soft limit is reached and remains reached for the specified number of
+# seconds (continuously).
+# So for instance if the hard limit is 32 megabytes and the soft limit is
+# 16 megabytes / 10 seconds, the client will get disconnected immediately
+# if the size of the output buffers reach 32 megabytes, but will also get
+# disconnected if the client reaches 16 megabytes and continuously overcomes
+# the limit for 10 seconds.
+#
+# By default normal clients are not limited because they don't receive data
+# without asking (in a push way), but just after a request, so only
+# asynchronous clients may create a scenario where data is requested faster
+# than it can read.
+#
+# Instead there is a default limit for pubsub and slave clients, since
+# subscribers and slaves receive data in a push fashion.
+#
+# Both the hard or the soft limit can be disabled by setting them to zero.
+client-output-buffer-limit normal 0 0 0
+client-output-buffer-limit slave 256mb 64mb 60
+client-output-buffer-limit pubsub 32mb 8mb 60
+
+# Redis calls an internal function to perform many background tasks, like
+# closing connections of clients in timeout, purging expired keys that are
+# never requested, and so forth.
+#
+# Not all tasks are performed with the same frequency, but Redis checks for
+# tasks to perform accordingly to the specified "hz" value.
+#
+# By default "hz" is set to 10. Raising the value will use more CPU when
+# Redis is idle, but at the same time will make Redis more responsive when
+# there are many keys expiring at the same time, and timeouts may be
+# handled with more precision.
+#
+# The range is between 1 and 500, however a value over 100 is usually not
+# a good idea. Most users should use the default of 10 and raise this up to
+# 100 only in environments where very low latency is required.
+hz 10
+
+# When a child rewrites the AOF file, if the following option is enabled
+# the file will be fsync-ed every 32 MB of data generated. This is useful
+# in order to commit the file to the disk more incrementally and avoid
+# big latency spikes.
+aof-rewrite-incremental-fsync yes
+
@@ -0,0 +1,11 @@
+. $(dirname $0)/test_helper.sh
+
+test_redis_running() {
+  assertTrue "redis running" 'run_on database pgrep -f redis'
+}
+
+test_redis_listens_on_local_network() {
+  assertTrue 'redis listening on local network' 'nc -z -w 1 $database 6379'
+}
+
+. shunit2
...	...	@@ -2,6 +2,7 @@ name 'database_server'
2	2	description 'Database server'
3	3	run_list *[
4	4	'recipe[postgresql]',
	5	+ 'recipe[redis]',
5	6	'recipe[postgresql::colab]',
6	7	'recipe[postgresql::gitlab]',
7	8	]
...	...
...	...	@@ -0,0 +1,13 @@
	1	+package 'redis'
	2	+
	3	+template '/etc/redis.conf' do
	4	+ user 'root'
	5	+ group 'root'
	6	+ mode 0644
	7	+
	8	+ notifies :restart, 'service[redis]'
	9	+end
	10	+
	11	+service 'redis' do
	12	+ action [:enable, :start]
	13	+end
...	...
...	...	@@ -0,0 +1,11 @@
	1	+. $(dirname $0)/test_helper.sh
	2	+
	3	+test_redis_running() {
	4	+ assertTrue "redis running" 'run_on database pgrep -f redis'
	5	+}
	6	+
	7	+test_redis_listens_on_local_network() {
	8	+ assertTrue 'redis listening on local network' 'nc -z -w 1 $database 6379'
	9	+}
	10	+
	11	+. shunit2
...	...