TIL
Short “Today I Learned” notes and practical snippets.
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Kubernetes: Projected Volume
Nov 5, 2021
In k8s world, sometimes you need to mount both configmap and secret under the same directory. Let's say you have to mount all of them under /etc/app such that the layout should look like this
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GNU Utility: Envsubst
Nov 5, 2020
Recently, I learnt about a new command: envsubst which is present by default. It substitutes the values of environment variables. This means, instead of using helm, we can use plain k8s manifest an...
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JVM: Options Config File
Oct 6, 2020
Java Virtual Machine (JVM) provides a mechanism to set JVM configuration options in jvm.options file. This file provide a way to tweak configuration based on JVM version too. Above configuration me...
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SQLite: WAL Mode
Oct 5, 2020
From SQLite v3.7.0, write-ahead logging (WAL) mode is available which has the following advantages: It is significantly faster. It enables more concurrency as readers don't block writers and vice...
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Container Signing Tool: Cosign
Oct 4, 2020
Cosign is tool developed by sigstore working group which takes care of container signing and verification. Let's first generate a key-pair: Now using the private key, we will sign a docker image.
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DuckDB: Query SQLite and PostgreSQL Data
Oct 4, 2020
DuckDB can query data stored in SQLite and PostgreSQL using SQLiteScanner and PostgresScanner respectively. DuckDB claims reads via DuckDB client will be faster than reads via their respective data...
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PostgreSQL: Verifying Index Corruption
Oct 4, 2020
Although glibc has some breaking changing with every minor version release but with v2.28, there are lots of breaking changes which will corrupt almost all Postgres indexes. In order to identify br...
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Python: Zip Application
Oct 4, 2020
From Python v2.6, they added the support of allowing python interpreter to execute a zip file. Let's see an example:
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SQLite: Index Recommendations
Oct 4, 2020
For databases, most of the read performance depends on indexing. SQLite has expert command which recommends the appropriate index creation based on the query.